Fix WorkersByJobId: Filtered Workers Not Empty Check

[kmg-stripe]

Context

I forgot to update the previous PR with this fix. We have enough cruft lying around from all of the churn, that we hit cases where we get a NPE when we cannot parse the worker payload in getAllWorkersByJobId. This checks to ensure workers is not empty before referencing the first element of workers.

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

537 tests  +214   531 ✅ +214   7m 46s ⏱️ + 1m 4s
139 suites + 44     6 💤 ±  0 
139 files   + 44     0 ❌ ±  0 

Results for commit 43f1c11. ± Comparison against base commit ef3ad82.

♻️ This comment has been updated with latest results.

[kmg-stripe]

@hmitnflx - If you have a sec, could you have a look at this one? Should be quick.

[crioux-stripe]

@Andyz26 Hey! One more for our production readiness if you don't mind.

[crioux-stripe]

@Andyz26 Sorry about self-approving on this one. I wanted to make sure @kmg-stripe could hit our target of releasing today.

[Andyz26]

@crioux-stripe no worries. I am on vacation and I will check with @hmit on this.