Add tests for getCredentials with multiple goproxy_servers and maven_…

[mario-campos]

This PR adds two new tests to the start-proxy action, to assert that registry configurations with more than one registry of the same kind (two goproxy_server and two maven_repository in this case) are parsed and reported appropriately. While one additional test would be sufficient to test this multi-registry use-case, I thought two tests across two languages offered a bit more safety.

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:

• Advanced setup - Impacts users who have custom CodeQL workflows.
• 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.

Environments:

• Testing/None - This change does not impact any CodeQL workflows in production.

How did/will you validate this change?

• Unit tests - I am depending on unit test coverage (i.e. tests in .test.ts files).

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

• Development/testing only - This change cannot cause any failures in production.

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

• Other - I expect a PR check to fail if these tests are implemented incorrectly.

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

Adds unit test coverage to ensure start-proxy’s getCredentials correctly returns multiple registry configurations of the same type for a given language.

Changes:

• Added a test verifying KnownLanguage.go returns all configured goproxy_server entries (and still includes git_source for Go).
• Added a test verifying KnownLanguage.java returns all configured maven_repository entries (and filters out non-Java registry types).