Last 13 characters of error output in 'C# Interactive' window are not colored red

Moved from https://github.com/dotnet/roslyn/issues/63317

**Version Used**: VS 17.3 (Roslyn 4.3.0.3-22401.3)

**Steps to Reproduce**:

1. Open the "C# Interactive" window in VS.
2. Submit any statement that results in error diagnostics.

**Expected Behavior**: All error diagnostics are colored correctly (red).

**Actual Behavior**: The last 13 characters are colored black, while the rest is colored correctly.


This does not affect `csi` in the console, which is always colored correctly.