Fix test failure for ResourceClusterActorTest

[hellolittlej]

Context

It's a classic Mockito multi-threading race condition. The actor starts in @before and runs background threads. When the test calls when(mantisJobStore.getTaskExecutor(...)) at line 960, Mockito records that invocation — but a background actor thread can call loadAllDisableTaskExecutorsRequests on the mock between Mockito's "record call" and the .thenReturn(...), causing the return value to be associated with the wrong method.

Checklist

• ./gradlew build compiles code correctly
• Added new tests where applicable
• ./gradlew test passes all tests
• Extended README or added javadocs where applicable

[github-actions]

Test Results

164 files  ±0  164 suites  ±0   10m 12s ⏱️ -56s
795 tests ±0  784 ✅ +2  11 💤 ±0  0 ❌  - 2 
795 runs   - 2  784 ✅ ±0  11 💤 ±0  0 ❌  - 2 

Results for commit 529ff14. ± Comparison against base commit b60f201.

♻️ This comment has been updated with latest results.