fix (#8258)

* fix

* test update

Author: markdevocht

ios/BottomTabPresenter.mm

@@ -38,7 +38,10 @@ - (void)mergeOptions:(RNNNavigationOptions *)mergeOptions
 
 - (void)createTabBarItem:(UIViewController *)child
         bottomTabOptions:(RNNBottomTabOptions *)bottomTabOptions {
-    child.tabBarItem = [_tabCreator createTabBarItem:bottomTabOptions mergeItem:child.tabBarItem];
+    UITabBarItem *updatedItem = [_tabCreator createTabBarItem:bottomTabOptions mergeItem:child.tabBarItem];
+    if (updatedItem != child.tabBarItem) {
+        child.tabBarItem = updatedItem;
+    }
 }
 
 @end

ios/RNNTabBarItemCreator.mm

@@ -5,7 +5,7 @@
 @implementation RNNTabBarItemCreator
 
 - (UITabBarItem *)createTabBarItem:(UITabBarItem *)mergeItem {
-    return [UITabBarItem new];
+    return mergeItem ?: [UITabBarItem new];
 }
 
 - (UITabBarItem *)createTabBarItem:(RNNBottomTabOptions *)bottomTabOptions

playground/ios/NavigationTests/BottomTabPresenterTest.mm

@@ -57,7 +57,7 @@ - (void)testMergeOptions_shouldSetTabBarItemColorWithDefaultOptions {
     XCTAssertEqual(self.componentViewController.tabBarItem.title, @"title");
 }
 
-- (void)testMergeOptions_shouldCreateNewTabBarItemInstance {
+- (void)testMergeOptions_shouldReuseExistingTabBarItemInstance {
     RNNNavigationOptions *defaultOptions = [RNNNavigationOptions emptyOptions];
     defaultOptions.bottomTab.selectedIconColor = [Color withColor:UIColor.greenColor];
     self.uut.defaultOptions = defaultOptions;
@@ -69,8 +69,8 @@ - (void)testMergeOptions_shouldCreateNewTabBarItemInstance {
     [self.uut mergeOptions:mergeOptions
            resolvedOptions:self.options
                      child:self.componentViewController];
-    UITabBarItem *newTabBarItem = self.componentViewController.tabBarItem;
-    XCTAssertNotEqual(currentTabBarItem, newTabBarItem);
+    UITabBarItem *updatedTabBarItem = self.componentViewController.tabBarItem;
+    XCTAssertEqual(currentTabBarItem, updatedTabBarItem);
 }
 
 @end