Default to StartProxyRemoveUnusedRegistries behaviour

[mbg]

Removes the StartProxyRemoveUnusedRegistries and defaults to the new behaviour.

Risk assessment

For internal use only. Please select the risk level of this change:

• Low risk: Changes are fully under feature flags, or have been fully tested and validated in pre-production environments and are highly observable, or are documentation or test only.

Which use cases does this change impact?

Workflow types:

• Managed - Impacts users with dynamic workflows (Default Setup, Code Quality, ...).

Products:

• Code Scanning - The changes impact analyses when analysis-kinds: code-scanning.
• Code Quality - The changes impact analyses when analysis-kinds: code-quality.
• Other first-party - The changes impact other first-party analyses.

Environments:

• Dotcom - Impacts CodeQL workflows on github.com and/or GitHub Enterprise Cloud with Data Residency.

How did/will you validate this change?

• Unit tests - I am depending on unit test coverage (i.e. tests in .test.ts files).
• End-to-end tests - I am depending on PR checks (i.e. tests in pr-checks).

If something goes wrong after this change is released, what are the mitigation and rollback strategies?

• Rollback - Change can only be disabled by rolling back the release or releasing a new version with a fix.

How will you know if something goes wrong after this change is released?

• Telemetry - I rely on existing telemetry or have made changes to the telemetry.
  • Dashboards - I will watch relevant dashboards for issues after the release. Consider whether this requires this change to be released at a particular time rather than as part of a regular release.
  • Alerts - New or existing monitors will trip if something goes wrong with this change.

Are there any special considerations for merging or releasing this change?

• No special considerations - This change can be merged at any time.

Merge / deployment checklist

• Confirm this change is backwards compatible with existing workflows.
• Consider adding a changelog entry for this change.
• Confirm the readme and docs have been updated if necessary.

[Copilot]

Pull request overview

Removes the StartProxyRemoveUnusedRegistries feature flag and makes its behaviour the default, so unused registries are always skipped based on the language being analysed.

Changes:

• Drop the feature flag and its featureConfig entry.
• Remove the old LANGUAGE_TO_REGISTRY_TYPE and rename the NEW_* variant to LANGUAGE_TO_REGISTRY_TYPE; simplify getCredentials by removing the skipUnusedRegistries parameter.
• Update start-proxy-action.ts to no longer query the flag, and adjust tests accordingly.

Show a summary per file

File	Description
src/start-proxy.ts	Consolidates registry mapping to one constant and removes the skipUnusedRegistries parameter from getCredentials.
src/start-proxy.test.ts	Updates tests to match the new signature and removes the now-redundant Actions test case.
src/start-proxy-action.ts	Removes the feature flag query and unused Feature import.
src/feature-flags.ts	Removes the StartProxyRemoveUnusedRegistries enum value and config entry.
lib/upload-lib.js, lib/entry-points.js	Generated JS reflecting the source changes.

Copilot's findings

• Files reviewed: 4/6 changed files
• Comments generated: 0