Turned off layout rounding for failing tests (#3942)

Some tests were failing if your resolution was 150% (not 100%).
This fixes the 3 failing tests.

## PR Type
What kind of change does this PR introduce?
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- Bugfix
<!-- - Feature -->
<!-- - Code style update (formatting) -->
<!-- - Refactoring (no functional changes, no api changes) -->
<!-- - Build or CI related changes -->
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<!-- - Sample app changes -->
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## What is the current behavior?
Tests fail if your display scale is 150%

## What is the new behavior?
Tests pass independently from your display scale.


## PR Checklist

Please check if your PR fulfills the following requirements:

- [X] Tested code with current [supported SDKs](../readme.md#supported)
- [ ] Pull Request has been submitted to the documentation repository [instructions](..\contributing.md#docs). Link: <!-- docs PR link -->
- [ ] Sample in sample app has been added / updated (for bug fixes / features)
    - [ ] Icon has been created (if new sample) following the [Thumbnail Style Guide and templates](https://github.com/windows-toolkit/WindowsCommunityToolkit-design-assets)
- [ ] New major technical changes in the toolkit have or will be added to the [Wiki](https://github.com/windows-toolkit/WindowsCommunityToolkit/wiki) e.g. build changes, source generators, testing infrastructure, sample creation changes, etc...
- [ ] Tests for the changes have been added (for bug fixes / features) (if applicable)
- [ ] Header has been added to all new source files (run *build/UpdateHeaders.bat*)
- [X] Contains **NO** breaking changes

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## Other information

Author: msftbot[bot]

UnitTests/UnitTests.UWP/UI/Controls/Test_WrapPanel_Visibility.cs

@@ -37,6 +37,8 @@ await App.DispatcherQueue.EnqueueAsync(async () =>
     </controls:WrapPanel>
 </Page>") as FrameworkElement;
 
+                treeRoot.UseLayoutRounding = false;
+
                 var expected = new (int u, int v, int w, int h)[]
                 {
                     (0, 0, 0, 0), // Collapsed
@@ -94,6 +96,8 @@ await App.DispatcherQueue.EnqueueAsync(async () =>
     </controls:WrapPanel>
 </Page>") as FrameworkElement;
 
+                treeRoot.UseLayoutRounding = false;
+
                 var expected = new (int u, int v, int w, int h)[]
                 {
                     (0, 0, 150, 50),
@@ -149,6 +153,8 @@ await App.DispatcherQueue.EnqueueAsync(async () =>
     </controls:WrapPanel>
 </Page>") as FrameworkElement;
 
+                treeRoot.UseLayoutRounding = false;
+
                 var expected = new (int u, int v, int w, int h)[]
                 {
                     (0, 0, 150, 50),