chore: makes HttpClient instance available for garbage collection

[mcollovati]

Allows the HttpClient default executor to be properly shutdown when HttpClient is not referenced anymore.

[mcollovati]

With this change, the following logs on shutdown/restart disappear

WARNING [Thread-20] --- org.apache.catalina.loader.WebappClassLoaderBase: The web application [ROOT] appears to have started a thread named [HttpClient-6-Worker-0] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 [email protected]/jdk.internal.misc.Unsafe.park(Native Method)
 [email protected]/java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:252)
 [email protected]/java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:401)
 [email protected]/java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:903)
 [email protected]/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1061)
 [email protected]/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1122)
 [email protected]/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
 [email protected]/java.lang.Thread.run(Thread.java:840)

[sonarcloud]

Quality Gate passed

Issues
22 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Test Results

1 159 files  ±0  1 159 suites  ±0   1h 35m 48s ⏱️ + 6m 37s
7 568 tests ±0  7 512 ✅ ±0  56 💤 ±0  0 ❌ ±0 
7 912 runs   - 2  7 848 ✅  - 1  64 💤  - 1  0 ❌ ±0 

Results for commit 1976bca. ± Comparison against base commit fb02577.

♻️ This comment has been updated with latest results.