feat(tab-bar): add overlay indicator option

[usmanvrtx]

Description

This PR adds an optional overlayIndicator property to the Ensemble TabBar. It allows the selected/focused indicator to overlap the divider, which is required for the Android TV TabBar layout.

Related Issue

N/A

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactoring (no functional changes)

What Has Changed

TabBar overlay indicator

• Added the nullable overlayIndicator boolean property.
• Added YAML support for both TabBar and ScrollableTabBar.
• Added schema metadata for the new property.
• Added overlay rendering for standard and TV TabBar implementations.
• Kept the existing divider and indicator behavior when the property is omitted or set to false.
• Preserved existing TV focus coordinates, navigation, scrolling, and tab selection behavior.

Usage

TabBar:
  styles:
    dividerColor: 0xFF232323
    dividerThickness: 3
    dividerPadding: 4 40 0 40
    overlayIndicator: true