Improve string comparison performance

[Nice3point]

The current version of the comparison is extremely inefficient. As you know ToLower is a rather slow operation, which may reduce performance for comparing a large number of strings. The best way is to use overloading with StringComparison support. But it is not available in Net framework.

I added the code and description from .Net 9 to support the method on any target framework. To prevent using from being marked unused in Net core and accidentally deleted, I added global using for extensions in the UI package.

Additionally I removed the Trim call, for URI comparison, URI does not support spaces and such call is useless, every call I debugged, everything compares correctly, previous behaviour is preserved with performance increase.

Before:

"text".Trim().ToLower().Contains("Text")

Now:

"text".Contains("Text", StringComparison.OrdinalIgnoreCase)

Benchmark for string pack://application:,,,/Wpf.Ui;component/Resources/Theme/Light.xaml:

Method	Mean	Error	StdDev	Allocated
ToLower	37.22 ns	2.117 ns	3.103 ns	160 B
OrdinalIgnoreCase	13.61 ns	0.138 ns	0.203 ns	-
InvariantCultureIgnoreCase	92.63 ns	0.656 ns	0.962 ns	-

StringComparison.OrdinalIgnoreCase 3 times faster without memory allocation.

Pull request type

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• Update
• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
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