Visual state perf

[dr1rrb]

• do not re-apply same visual state on each windows size changed
• clear only setters that won't be updated by the target visual state

PR Type

What kind of change does this PR introduce?

• Other: Perf optimisations

What is the current behavior?

• Each time the window is resized, the state triggers are re-evaluated and the target state is re-applied no matter if it has changed or not
• When we go from a state to another state, we clear the value of all Setters of the current state before applying the Setters of the target state

What is the new behavior?

• We do not re-apply the VisualState if it's already the current one
• We clear only Setters that won't be affected by the target state.

PR Checklist

• Tested code with current supported SDKs
• Docs have been added/updated which fit documentation template. (for bug fixes / features)
• Unit Tests and/or UI Tests for the changes have been added (for bug fixes / features) (if applicable)
• Wasm UI Tests are not showing unexpected any differences
• Contains NO breaking changes
• Updated the Release Notes
• Associated with an issue (GitHub or internal)

Other information

This is part of a bigger changes set that will add Unit test for this feature

Internal Issue (If applicable):
https://nventive.visualstudio.com/_workitems/edit/154623

[jeromelaban]

You should be able to add a test with something similar to https://github.com/nventive/Uno/blob/086865bc298818a894c050d11638fd25ec5bd1db/src/Uno.UI.Tests/Windows_UI_Xaml_Controls/xLoad/Given_xLoadSetters.cs#L17.

by testing the changes in the DP callback.