[Windows] Fix for FontImageSource color is not applied to the Tab Icon on the TabbedPage

[Tamilarasan-Paranthaman]

Root Cause of the issue

• The FontImageSource icon color is not considered when applying the Icon's Foreground

Description of Change

• The issue was resolved by storing the FontImageSource icon color in the IconColor property of the ViewModel. If IconColor is not null, the Foreground property retrieves the icon color and applies it to the icon's foreground. If IconColor is null, the Foreground property uses the SelectedForeground and UnselectedForeground values based on the IsSelected property and applies them to the icon's foreground.
• Additionally, I have handled the dynamic updates to the Icon and IconColor properties in the OnPagePropertyChanged method

Issues Fixed

Fixes #26752

Test Case

• The test case has already been added in the following PR. We can reenable it for Windows once the PR has been merged.
• [iOS] [Android] Fix for the FontImageSource color is not applied properly to the Tab Icon #26757

Tested the behaviour in the following platforms

• Windows
• Android
• iOS
• Mac

Screenshot

Before Issue Fix	After Issue Fix

[dotnet-policy-service]

Hey there @Tamilarasan-Paranthaman! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.