Fix Streamable.forEach BiConsumer overload ignoring executor

src/main/java/io/reactivex/rxjava4/internal/operators/streamable/StreamableForEach.java

@@ -105,7 +105,7 @@ public static <T> CompletionStageDisposable<Void> forEach(
                 throw ExceptionHelper.wrapOrThrow(finallyCrash);
             }
             return null;
-        });
+        }, executor);
         canceller.add(Disposable.fromFuture(future));
         return new CompletionStageDisposable<>(future, canceller);
     }

src/test/java/io/reactivex/rxjava4/internal/operators/streamable/StreamableForEachTest.java

@@ -134,6 +134,25 @@ public void forEachBiUncheckedPropagation() throws Throwable {
         });
     }
 
+    @Test
+    public void forEachBiUsesProvidedExecutor() throws Throwable {
+        var expectedThread = new AtomicReference<Thread>();
+        var actualThread = new AtomicReference<Thread>();
+        try (var executor = Executors.newSingleThreadExecutor(run -> {
+            var thread = new Thread(run, "RxJava-Test-Executor");
+            expectedThread.set(thread);
+            return thread;
+        })) {
+            var canceller = new CompositeDisposable();
+
+            Streamable.just(1)
+            .forEach((_, _) -> actualThread.set(Thread.currentThread()), canceller, executor)
+            .await();
+
+            assertSame(expectedThread.get(), actualThread.get());
+        }
+    }
+
     @Test
     public void forEachOutsideCancel() {
         var cd = new CompositeDisposable();