[Testing] Re-enable CachedFilenameIsCorrectAndValid test

[jsuarezruiz]

Description of Change

The runtime issue has been resolved in .NET 10.0 and test CachedFilenameIsCorrectAndValid has been already enabled. Based on the original issue dotnet/runtime#111506, this PR include some tests in the UriImageSourceServiceTests.cs file to specifically verify that the String.Replace() method with StringComparison.OrdinalIgnoreCase works correctly across all platforms.

Issues Fixed

Fixes #27317

[Copilot]

Pull Request Overview

This PR re-enables a previously disabled test and adds comprehensive regression tests to verify that String.Replace() with StringComparison.OrdinalIgnoreCase works correctly across all platforms in .NET 10.0. The original issue was a runtime bug that caused "IndexOf with matchLength" errors when using case-insensitive string replacement operations.

• Adds four new test methods to verify different scenarios of case-insensitive string replacement
• Includes tests for basic replacement, multiple occurrences, special characters, and long strings
• Provides regression coverage for the resolved .NET runtime issue #111506

Comments suppressed due to low confidence (3)

src/Core/tests/DeviceTests/Services/ImageSource/UriImageSourceServiceTests.cs:26

• The test method name 'StringReplaceWithMultipleOccurrences' is too generic for the MAUI codebase context. Consider renaming to 'CachedFilenameTemplateWithMultipleHashPlaceholders' or similar to reflect its relationship to image caching functionality.

		// Tests String.Replace with multiple occurrences of the search string

src/Core/tests/DeviceTests/Services/ImageSource/UriImageSourceServiceTests.cs:36

• The test method name 'StringReplaceWithSpecialCharacters' is too generic. Consider renaming to 'CachedFilenameHandlesSpecialCharactersInHash' to better reflect its purpose in the image source service context.

		// Tests String.Replace with special characters in template and replacement

src/Core/tests/DeviceTests/Services/ImageSource/UriImageSourceServiceTests.cs:46

• The test method name 'StringReplaceWithLongStrings' is too generic. Consider renaming to 'CachedFilenameHandlesLongHashValues' to better align with the image source service domain.

		// Tests String.Replace with a long template and replacement

[rmarinho]

Failing test not related