Suppress security-report-schema deprecation warning for GitLab vendored analyzers

Context

With Deprecate security report schemas version 14-x-x (#366477 - closed) we introduced a warning to announce the deprecation of 14.x.x schemas. This is important to announce well in advance of the release so integrators can be made aware.

Due to release constraints and other coordination complexities across GitLab analyzer groups, the analyzer versions that support the latest schema will only be available in GitLab %16.0.

This deprecation warning is confusing to customers who are running GitLab scanners because there is yet no action for them to take to avoid the warning.

Proposal

1. Suppress the deprecation warning for all GitLab-vendored analyzers which we can expect will be upgraded in time for %16.0 since those are within our control.
2. Evaluate whether this same scenario is likely to occur again for GitLab analyzers, and update the deprecation process accordingly.

Implementation plan

1. Suppress warning in lib/gitlab/ci/parsers/security/validators/schema_validator.rb
2. Evaluate deprecation process and create follow-up issue(s)