Handle NaN and Infinity in CSharpHelper.Literal(float)

[ilkertskn]

• Return float.NaN, float.PositiveInfinity, and float.NegativeInfinity instead of invalid literals such as "NaNf", "Infinityf", and "-Infinityf" that do not compile
• Mirrors the existing NaN/Infinity handling for double
• Add float NaN/Infinity cases to CSharpHelperTest.Literal_works

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        Fixes #bugnumber

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[Copilot]

Pull request overview

This PR fixes C# code generation for float literals in CSharpHelper by emitting valid, compilable expressions for NaN and infinities (matching the existing behavior for double).

Changes:

• Update CSharpHelper.Literal(float) to return float.NaN, float.PositiveInfinity, and float.NegativeInfinity for the corresponding special values.
• Add test coverage for these float special cases in CSharpHelperTest.Literal_works.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
test/EFCore.Design.Tests/Design/Internal/CSharpHelperTest.cs	Adds float NaN/Infinity InlineData cases to validate the new literal formatting.
src/EFCore.Design/Design/Internal/CSharpHelper.cs	Implements special-case handling for float NaN/Infinity to avoid emitting invalid literals like NaNf/Infinityf.

[ilkertskn]

@dotnet-policy-service agree

[AndriySvyryd]

Thanks for your contribution!