SourceKit-LSP diagnosis progress is not very accurate

[award999]

Describe the bug
The % counter goes up and down, so hard to get a sense the real progress.

To Reproduce
Steps to reproduce the behavior:

1. Generate a diagnostic bundle, selecting full diagnostics
2. Watch the "Diagnosing SourceKit-LSP: x%" progress notification
3. Notice it goes up to 6 or 7%, dropping to 0 eventually and counting up again. Never seen it get above 10%

Screen.Recording.2025-08-20.at.8.49.12.AM.mov

Expected behavior
More accurate progress and do we maybe actually increment so the bar fills

Environment
All environments

Additional context
N/A