Memory leak on TintedImageBehavior fix

[Marioo1357]

We subscribe to OnElementPropertyChanged only once - OnAttached - instead of each time the TintColor is changed

Every time when color was applied, the void was added to event handler. It causes that every next ImageSource change, invoked heavy color logic multiple times

Description of Change

Move dispose and subscibe logic right place in ImageTintBehavior

Linked Issues

• Fixes [BUG] IconTintColorBehavior huge memory leak and app freeze on Android #1612

PR Checklist

• Has a linked Issue, and the Issue has been approved(bug) or Championed (feature/proposal)
• Has tests (if omitted, state reason in description)
• Has samples (if omitted, state reason in description)
• Rebased on top of main at time of PR
• Changes adhere to coding standard
• Documentation created or updated: https://github.com/MicrosoftDocs/CommunityToolkit/pulls

Additional information

[Marioo1357]

@dotnet-policy-service agree

[VladislavAntonyuk]

Thank you!
Just add some explanation: we subscribe to OnElementPropertyChanged only once - OnAttached - instead of each time the TintColor is changed

[Marioo1357]

PR has:

• no test because the tests on native code are not supported
• no any additional samples, because current is enough
• no documentation updated, because there is no change in any behaviour