Drop clusters_applications_helm

We're cleaning up the deprecated Clusters::Applications code related to Remove clusters_applications_* code (#366573 - closed)

Application code that used this table was removed in Clusters::Applications models removal (#388696 - closed)

In !117460 (merged) we dropped the foreign keys. This was in post deploy migration that has been run.

This MR's purpose is to

• drop the clusters_applications_helm table
• move the dictionary files per these instructions

For transparency, this was originally part of a single MR that drops many clusters_applications* tables, but sensing some concern around this I have split them into individual MRs.

Table usage

Thanos Query showing table usage. It's non-zero but very tiny. I don't think it represents application usage with it being this small but would love a Database reviewer's insight on this.

Migration output

main: == [advisory_lock_connection] object_id: 275040, pg_backend_pid: 31775
main: == 20230502193525 DropClustersApplicationsHelm: migrating =====================
main: -- drop_table(:clusters_applications_helm)
main:    -> 0.0031s
main: == 20230502193525 DropClustersApplicationsHelm: migrated (0.0253s) ============

main: == [advisory_lock_connection] object_id: 275040, pg_backend_pid: 31775
ci: == [advisory_lock_connection] object_id: 275240, pg_backend_pid: 31777
ci: == 20230502193525 DropClustersApplicationsHelm: migrating =====================
ci: -- drop_table(:clusters_applications_helm)
ci:    -> 0.0011s
ci: == 20230502193525 DropClustersApplicationsHelm: migrated (0.0089s) ============

ci: == [advisory_lock_connection] object_id: 275240, pg_backend_pid: 31777