feat(datasource/java-version): allow custom registry URLs

[palakkhinvasara]

Summary

• datasource/java-version: add customRegistrySupport #45026

Allow custom registry URLs to be specified for the Java Version datasource.

Changes

• Enabled custom registry support for the Java Version datasource.
• Updated getReleases to correctly handle custom registry URLs with or without a trailing /.
• Added a test verifying releases can be fetched from a custom registry URL.
• Updated existing snapshots to reflect normalized registry URLs.

Testing

• Added coverage for custom registry URL handling.
• Verified the existing Java Version datasource tests continue to pass.

pnpm exec vitest run lib/modules/datasource/java-version/index.spec.ts

Result:

Test Files  1 passed (1)
Tests       11 passed (11)

Checklist

• Enable customRegistrySupport
• Update getReleases to honor the passed registry URL
• Add custom registry URL test
• Update snapshots
• Verify all Java Version datasource tests pass