fix: FormFixHome is messed up HiDPI

[RussKie]

Relates to #4099
Fixes #4690

Screenshots before and after (if PR changes UI):
150% scaling (before / after)

What did I do to test the code and ensure quality:

• run it manually at various scaling

Has been tested on (remove any that don't apply):

• Windows 10
• 34" 4K monitor

[codecov]

Codecov Report

Merging #4755 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4755      +/-   ##
==========================================
- Coverage   29.92%   29.92%   -0.01%     
==========================================
  Files         516      516              
  Lines       41644    41644              
  Branches     5901     5901              
==========================================
- Hits        12463    12460       -3     
- Misses      28671    28673       +2     
- Partials      510      511       +1

Impacted Files	Coverage Δ
GitUI/Editor/Diff/LinePrefixHelper.cs	95.83% <0%> (-4.17%)	⬇️
GitUI/Hotkey/HotkeySettingsManager.cs	79.67% <0%> (-0.55%)	⬇️
GitUI/Editor/FileViewer.cs	19.49% <0%> (-0.19%)	⬇️
...itUI/UserControls/RevisionGridClasses/DvcsGraph.cs	23.85% <0%> (-0.16%)	⬇️
GitUI/FormStatus.cs	12.5% <0%> (ø)	⬆️
GitCommands/Settings/AppSettings.cs	26.94% <0%> (+0.16%)	⬆️

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[drewnoakes]

Looks good on my 200% scaled screen.

[drewnoakes]

This fixes #4690.

[RussKie]

Awesome, thanks