RCS1198: false positive with interpolated strings in .NET 6

**Product and Version Used**:
Microsoft Visual Studio Community 2019 Version 16.10.4
Roslynator.Formatting.Analyzers 1.2.1 via Nuget
[RCS1198](https://github.com/JosefPihrt/Roslynator/blob/master/docs/analyzers/RCS1198.md)
[IDE0071](https://docs.microsoft.com/ru-ru/dotnet/fundamentals/code-analysis/style-rules/ide0071)

**Steps to Reproduce**:
```csharp
enum Foo
{
A = 0
}

var test1 = $"Test foo = {Foo.A}."; // Get diagnostic for RCS1198.
var test2 = $"Test foo = {Foo.A.ToString()}."; // Get diagnostic for IDE0071.
```

**Actual Behavior**:
Get diagnostic for RCS1198 in interpolated strings.

**Expected Behavior**:
No diagnostic for RCS1198 in interpolated strings, because `ToString()` would be implicitly invoked by the compiler.

Start with the linked RCS1198 documentation and reproduce the two interpolated-string examples in the stated Visual Studio and Roslynator setup. Done means the first example no longer receives an RCS1198 diagnostic because interpolation already invokes ToString implicitly.

Written by the indexing model from the issue text.