Fix S2589 FP: Rule ignores case guards

Description

S2589 is raised on a switch expression on a tuple where the second parameter is discarded but for the first one there is a guard clause.

Repro steps

 private static string Example(string input, bool y)
    {
        return (input, y) switch
        {
            ("Foo", true) => "FooTrue",
            ("Foo", false) => "FooFalse",
            (var x, true) when x.StartsWith("ab") => "AbTrue",
            (var x, _) when x.StartsWith("CD") => "CD",
            _ => "empty",
        };
    }

Expected behavior

S2589 is not raised

Actual behavior

S2589 is raised on the line containing: (var x, _) when x.StartsWith("CD") => "CD",

Known workarounds

None/ Disable with pragma

Related information

C#/VB.NET Plugins version: 9.32
Visual Studio version: N/A -> Rider 2024.2.4
MSBuild / dotnet version: .net8.0
SonarScanner for .NET version (if used): N/A
Operating System: Ubuntu 22.04 LTS

Kindof relates to: https://github.com/SonarSource/sonar-dotnet/issues/8008

SonarSource / sonar-dotnet