Revise `CreateFromFilteredSolutionFile` implementation for trailing comma (and allowing comments)

[Youssef1313]

The current implementation of this method doesn't seem to allow trailing commas (and comments).

MSBuild supported trailing commas (and comments) of slnf files in dotnet/msbuild#6346

sdk/src/Cli/dotnet/SlnFileFactory.cs

Line 92 in f578225

JsonElement root = JsonDocument.Parse(File.ReadAllText(filteredSolutionPath)).RootElement;

@baronfel @rainersigwald Another discrepancy due to not having a unified implementation/helper for how to parse solutions and solution filters. Not specific to test command this time :)