Fix AttachedDropShadow size changes abnormally

[chenjt2001]

Fixes #4548

Fix AttachedDropShadow size changes abnormally.

PR Type

What kind of change does this PR introduce?
Bugfix

What is the current behavior?

The mask does not update even if the size of the element that owns the AttachedDropShadow changes.

What is the new behavior?

If the size of the element that owns the AttachedDropShadow changes, the mask will be updated.

PR Checklist

Please check if your PR fulfills the following requirements:

• [X] Created a feature/dev branch in your fork (vs. submitting directly from a commit on main)
• [X] Based off latest main branch of toolkit
• [X] Tested code with current supported SDKs
• [X] Contains NO breaking changes

Other information

[ghost]

Thanks chenjt2001 for opening a Pull Request! The reviewers will test the PR and highlight if there is any conflict or changes required. If the PR is approved we will proceed to merge the pull request 🙌

[chenjt2001]

I am not sure whether the sample app needs to be modified. I tested these commits with a simple project (Similar to code in #4548)

[LalithaNadimpalli]

The PR fixes the shadow to remain constant when we change the window size