Setting SelectionForegroundBrush for TextBox kills performance

[HermanKirshin]

Describe the bug

Selection in TextBox becomes too slow with large amount of text

TextPresenter.CreateTextLayout has condition that initializes textStyleOverrides when SelectionForegroundBrush is not null

Avalonia/src/Avalonia.Controls/Presenters/TextPresenter.cs

Line 555 in 49fb9ff

if (length > 0 && SelectionForegroundBrush != null)

And in case FormattedTextSource.CreateTextStyleRun receives non-empty collection in textModifier parameter it executes main part of method's body which works slowly with big amounts of text.

Avalonia/src/Avalonia.Base/Media/TextFormatting/FormattedTextSource.cs

Line 54 in 49fb9ff

if (textModifier == null || textModifier.Count == 0)

To Reproduce

Create simple multiline TextBox and set SelectionForegroundBrush to any value.
<TextBox Name="TextBox" AcceptsReturn="True" SelectionForegroundBrush="Blue" />
And fill it with a quite large amount of text (200kb).
Try to select anything - selection works with freezes.

Expected behavior

No response

Avalonia version

11.1.3

OS

No response

Additional context

sample_text.txt