Fix executor shutdown race in PII masking tests

Remove simulateInitializationComplete() from PII masking tests that
only verify queue contents. The call triggers processAll() ->
shutdownBackgroundExecutorAsync() which can race with the next test's
executor setup, causing testInitializeInBackground_WithConfig to fail.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: franco-zalamena-iterable

iterableapi/src/test/java/com/iterable/iterableapi/IterableAsyncInitializationTest.java

@@ -1079,8 +1079,9 @@ public void testPIIMasking_EmailMasked() throws InterruptedException {
             }
         }
 
-        // Complete initialization
-        IterableBackgroundInitializer.simulateInitializationComplete();
+        // No need to call simulateInitializationComplete() here — tearDown resets state.
+        // Calling it would trigger processAll() -> shutdownBackgroundExecutorAsync() which
+        // can race with the next test's executor setup.
     }
 
     @Test
@@ -1153,8 +1154,7 @@ public void testPIIMasking_AuthTokenMasked() throws InterruptedException {
             }
         }
 
-        // Complete initialization
-        IterableBackgroundInitializer.simulateInitializationComplete();
+        // No need to call simulateInitializationComplete() — tearDown resets state.
     }
 
     @Test
@@ -1207,8 +1207,7 @@ public void testPIIMasking_VerifyExactFormat() throws InterruptedException {
         assertTrue("UserId 'user_123_abc' should be masked to 'u***'", foundUserId1Masked);
         assertTrue("Email 'a@b.com' should be masked to 'a***'", foundEmail2Masked);
 
-        // Complete initialization
-        IterableBackgroundInitializer.simulateInitializationComplete();
+        // No need to call simulateInitializationComplete() — tearDown resets state.
     }
 
     // ========================================