fix Transitioning Content Control DPI issue

[ChrisPulman]

RenderTargetBitmap take an int therefore the minimum input value must be 1.

What kind of change does this PR introduce?

fix #2801

What is the current behaviour?

Transitioning Content Control has a DPI issue with a calculation returning less than 1;

What is the new behaviour?

Transitioning Content Control handles DPI issue with a calculation returning less than 1 but being resolved to 1;

What might this PR break?

none as is only used for animation.

Please check if the PR fulfils these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Other information:

[codecov]

Codecov Report

Merging #2827 (075f60b) into main (de9557f) will increase coverage by 1.72%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #2827      +/-   ##
==========================================
+ Coverage   68.28%   70.01%   +1.72%     
==========================================
  Files         137      137              
  Lines        4787     4792       +5     
==========================================
+ Hits         3269     3355      +86     
+ Misses       1518     1437      -81     

Impacted Files	Coverage Δ
src/ReactiveUI.Wpf/TransitioningContentControl.cs	58.23% <100.00%> (+45.50%)	⬆️
src/ReactiveUI.Wpf/ReactiveWindow.cs	72.72% <0.00%> (+72.72%)	⬆️

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[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.