Fixes #1702: Fixed Memory Leak in MediaElement

[marco-skizza]

Description of Change

Fixed Memory Leak in MediaElement.
The timer is now disposed as well.

Linked Issues

• Fixes [BUG] MediaElement is not currently being Garbage Collected #1702

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

Tested on: WinUI, Android, iOS

My Issues hasn't been approved yet, but I thought I nevertheless share my findings with this PR.
I hope you can merge it, in order to improve memory management for people using the MediaElement.

P.S.:
As mentioned in the Issue, besides disposing the handler, I had to dispose the MediaElement itself as well to get rid of the Memory Leak:

        MyMediaElement.Handler?.DisconnectHandler();
        MyMediaElement.Dispose();

But I think this can be added to the docu+sample later on...

Many thanks!

[marco-skizza]

@dotnet-policy-service agree company="Kanton Luzern"

[pictos]

Good catch!