fix(ios, afterInitialTab): ensure initial tab mounts before other tabs.

Updated `BottomTabsAfterInitialTabAttacher` to asynchronously attach other tabs
 after the initial tab's `componentDidMount` is called.

Author: asafkorem

lib/ios/BottomTabsAfterInitialTabAttacher.m

@@ -7,7 +7,9 @@ - (void)attach:(UITabBarController *)bottomTabsController {
     [bottomTabsController.selectedViewController setReactViewReadyCallback:^{
       [bottomTabsController readyForPresentation];
       for (UIViewController *viewController in bottomTabsController.deselectedViewControllers) {
+        dispatch_async(dispatch_get_main_queue(), ^{
           [viewController render];
+        });
       }
     }];
 

playground/ios/NavigationTests/RNNCommandsHandlerTest.m

@@ -554,8 +554,21 @@ - (void)testSetRoot_withBottomTabsAttachModeAfterInitialTab {
            }];
 
     [self waitForExpectationsWithTimeout:10 handler:nil];
-    XCTAssertTrue(_vc1.isViewLoaded);
-    XCTAssertTrue(_vc2.isViewLoaded);
+
+	XCTAssertTrue(self->_vc1.isViewLoaded);
+
+	// Make sure the view is not loaded until the next main run loop.
+	XCTAssertFalse(self->_vc2.isViewLoaded);
+
+
+	// Wait for the next main run-loop.
+	XCTestExpectation *viewLoadedExpectation = [self expectationWithDescription:@"Wait for _vc2.isViewLoaded"];
+	dispatch_async(dispatch_get_main_queue(), ^{
+		XCTAssertTrue(self->_vc2.isViewLoaded);
+		[viewLoadedExpectation fulfill];
+	});
+
+	[self waitForExpectationsWithTimeout:1 handler:nil];
 }
 
 - (void)testSetRoot_withAnimation {