Code action preview shows "no issues found" even if there are conflicts or issues

[jasonmalinowski]

Version Used: Version 17.0.0 Preview 4.0 [31631.564.main]

Steps to Reproduce:

1. Paste in to a project:

int i = 0;
Console.WriteLine(i);
Interlocked.Increment(ref i);

2. Invoke inline temporary on i.
3. Open the preview window,

Expected Behavior:

The preview doesn't say "no issues found", since we are failing to show conflicts.

Actual Behavior:

Note: we don't seem to show squiggles in the preview changes window either; so I don't think it will show errors in that case either.

[jasonmalinowski]

As far as I'm concerned, it's entirely OK to fix this bug by hiding that "no issues found" section; I assume the editor has an easy way to do that like we did for other stuff in #55775.