Provider crashes due to segmentation error

## Bug Report

Relevant Terraform Configuration

Image : hashicorp/terraform:1.2.6

Relevant Terraform Command

terraform apply -auto-approve

Relevant Log Output

These are the debug logs of the `terraform` command output:

[31m╷[0m[0m
[31m│[0m [0m[1m[31mError: [0m[0m[1mRequest cancelled[0m
[31m│[0m [0m
[31m│[0m [0m[0mThe plugin6.(*GRPCProvider).UpgradeResourceState request was cancelled.
[31m╵[0m[0m
[31m╷[0m[0m
[31m│[0m [0m[1m[31mError: [0m[0m[1mPlugin did not respond[0m
[31m│[0m [0m
[31m│[0m [0m[0mThe plugin encountered an error, and failed to respond to the
[31m│[0m [0mplugin6.(*GRPCProvider).ApplyResourceChange call. The plugin logs may
[31m│[0m [0mcontain more details.
[31m╵[0m[0m
[31m╷[0m[0m
[31m│[0m [0m[1m[31mError: [0m[0m[1mPlugin did not respond[0m
[31m│[0m [0m
[31m│[0m [0m[0mThe plugin encountered an error, and failed to respond to the
[31m│[0m [0mplugin6.(*GRPCProvider).ApplyResourceChange call. The plugin logs may
[31m│[0m [0mcontain more details.
[31m╵[0m[0m
[31m╷[0m[0m
[31m│[0m [0m[1m[31mError: [0m[0m[1mPlugin did not respond[0m
[31m│[0m [0m
[31m│[0m [0m[0mThe plugin encountered an error, and failed to respond to the
[31m│[0m [0mplugin6.(*GRPCProvider).ApplyResourceChange call. The plugin logs may
[31m│[0m [0mcontain more details.
[31m╵[0m[0m
[31m╷[0m[0m
[31m│[0m [0m[1m[31mError: [0m[0m[1mPlugin did not respond[0m
[31m│[0m [0m
[31m│[0m [0m[0mThe plugin encountered an error, and failed to respond to the
[31m│[0m [0mplugin6.(*GRPCProvider).ApplyResourceChange call. The plugin logs may
[31m│[0m [0mcontain more details.
[31m╵[0m[0m
[31m╷[0m[0m
[31m│[0m [0m[1m[31mError: [0m[0m[1mPlugin did not respond[0m
[31m│[0m [0m
[31m│[0m [0m[0mThe plugin encountered an error, and failed to respond to the
[31m│[0m [0mplugin6.(*GRPCProvider).ApplyResourceChange call. The plugin logs may
[31m│[0m [0mcontain more details.
[31m╵[0m[0m
[31m╷[0m[0m
[31m│[0m [0m[1m[31mError: [0m[0m[1mRequest cancelled[0m
[31m│[0m [0m
[31m│[0m [0m[0mThe plugin6.(*GRPCProvider).UpgradeResourceState request was cancelled.
[31m╵[0m[0mStack trace from the terraform-provider-gitlab_v16.9.1 plugin:panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xdf6436]goroutine 147 [running]:
gitlab.com/gitlab-org/terraform-provider-gitlab/internal/provider.(*gitlabPipelineScheduleResource).Update(0xc000552028, {0x125d6d8, 0xc0003cfcb0}, {{{{0x1262f00, 0xc0005d8720}, {0xf087c0, 0xc0005d8600}}, {0x1264df8, 0xc0006309b0}}, {{{0x1262f00, ...}, ...}, ...}, ...}, ...)
gitlab.com/gitlab-org/terraform-provider-gitlab/internal/provider/resource_gitlab_pipeline_schedule.go:370 +0x8b6
github.com/hashicorp/terraform-plugin-framework/internal/fwserver.(*Server).UpdateResource(0xc0003beb60, {0x125d6d8, 0xc0003cfcb0}, 0xc000815480, 0xc000815458)
github.com/hashicorp/terraform-plugin-framework@v1.5.0/internal/fwserver/server_updateresource.go:122 +0x6ee
github.com/hashicorp/terraform-plugin-framework/internal/fwserver.(*Server).ApplyResourceChange(0xc0003beb60, {0x125d6d8, 0xc0003cfcb0}, 0xc000ab58b0, 0xc000815640)
github.com/hashicorp/terraform-plugin-framework@v1.5.0/internal/fwserver/server_applyresourcechange.go:102 +0x192
github.com/hashicorp/terraform-plugin-framework/internal/proto6server.(*Server).ApplyResourceChange(0xc0003beb60, {0x125d6d8?, 0xc0003cfbc0?}, 0xc000ab5810)
github.com/hashicorp/terraform-plugin-framework@v1.5.0/internal/proto6server/server_applyresourcechange.go:55 +0x38e
github.com/hashicorp/terraform-plugin-mux/tf6muxserver.(*muxServer).ApplyResourceChange(0xc000249180, {0x125d6d8?, 0xc0003cf590?}, 0xc000ab5810)
github.com/hashicorp/terraform-plugin-mux@v0.14.0/tf6muxserver/mux_server_ApplyResourceChange.go:36 +0x193
github.com/hashicorp/terraform-plugin-go/tfprotov6/tf6server.(*server).ApplyResourceChange(0xc000247860, {0x125d6d8?, 0xc0003ce930?}, 0xc000234000)
github.com/hashicorp/terraform-plugin-go@v0.21.0/tfprotov6/tf6server/server.go:845 +0x3d0
github.com/hashicorp/terraform-plugin-go/tfprotov6/internal/tfplugin6._Provider_ApplyResourceChange_Handler({0x1055be0, 0xc000247860}, {0x125d6d8, 0xc0003ce930}, 0xc0001c8980, 0x0)
github.com/hashicorp/terraform-plugin-go@v0.21.0/tfprotov6/internal/tfplugin6/tfplugin6_grpc.pb.go:518 +0x1a6
google.golang.org/grpc.(*Server).processUnaryRPC(0xc0001c1000, {0x125d6d8, 0xc0003ce8a0}, {0x1263978, 0xc0003be000}, 0xc0004d05a0, 0xc000484c90, 0x1908318, 0x0)
google.golang.org/grpc@v1.61.0/server.go:1385 +0xdd1
google.golang.org/grpc.(*Server).handleStream(0xc0001c1000, {0x1263978, 0xc0003be000}, 0xc0004d05a0)
google.golang.org/grpc@v1.61.0/server.go:1796 +0xfb8
google.golang.org/grpc.(*Server).serveStreams.func2.1()
google.golang.org/grpc@v1.61.0/server.go:1029 +0x8b
created by google.golang.org/grpc.(*Server).serveStreams.func2 in goroutine 12
google.golang.org/grpc@v1.61.0/server.go:1040 +0x125Error: The terraform-provider-gitlab_v16.9.1 plugin crashed!This is always indicative of a bug within the plugin. It would be immensely
helpful if you could report the crash with the plugin's maintainers so that it
can be fixed. The output above should help diagnose the issue.

Additional Details

• GitLab Terraform Provider Version: `gitlab v16.9.1`
• GitLab Version: `GitLab Enterprise Edition 16.10.0-pre 1ba3f3dee89`
• Terraform Version: `hashicorp/terraform:1.2.6`