Added support for barTintColor in android ios

[shubhamguptadream11]

Part of this: https://github.com/okwasniewski/react-native-bottom-tabs/issues/11

Summary: This PR updates the tab bar background color for both iOS and Android implementations.

Changes Made:

iOS: Added the updateTabBarAppearance(with:) function to set the background color using UITabBarAppearance for iOS 15 and barTintColor for earlier versions

Android: Updated the tab bar background color to apply uniformly.

Testing:

• Verified background color changes on both iOS and Android.
• Added FourTabsWithBarTintColor for visual changes.

Adding snapshot of changes here:

iOS:

Android: