Add Gradle cache to setup-java steps in CI workflows

[dbwiddis]

Description

Adds cache: gradle to all actions/setup-java steps across GitHub Actions workflow files. This enables the built-in dependency caching provided by the setup-java action, which caches Gradle dependencies between workflow runs to reduce build times.

Changes

• Added cache: gradle to all 9 setup-java steps across 5 workflow files:
  • CI.yml (6 steps: spotless, javadoc, build, integTest, integMultiNodeTest, integTenantAwareTest)
  • publish-snapshots.yml (1 step)
  • test-api-consistency.yml (1 step)
  • test_bwc.yml (1 step)
  • test_security.yml (1 step)
• Bumped setup-java from v3 to v4 in test-api-consistency.yml for consistency with other workflows

Reference

• actions/setup-java caching documentation

Issues Resolved

N/A

Check List

• New functionality includes testing
  • N/A (infrastructure-only change, CI runs will validate)
• New functionality has been documented
  • N/A
• Commits are signed per the DCO using --signoff

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.38%. Comparing base (f235210) to head (95b2109).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1372      +/-   ##
============================================
- Coverage     78.38%   78.38%   -0.01%     
- Complexity     1306     1308       +2     
============================================
  Files           106      106              
  Lines          6015     6019       +4     
  Branches        640      641       +1     
============================================
+ Hits           4715     4718       +3     
+ Misses         1013     1012       -1     
- Partials        287      289       +2     

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