`Files to analyze` count doesn't stack in multi-workspace scenarios

[StellaHuang95]

Repro Steps

1. Open a folder in VSCode that contains both python files and notebooks, with the kernel of the notebooks set to a different Python interpreter than the rest of the files.
2. Observer the xxx files to analyze in the status bar at left bottom corner.

Expected behavior

The files to analyze count should either stack independently for each workspace, reflecting the count specific to each workspace, or it should display the total file count across all workspaces

Actual behavior

The files to analyze count initially displays the count for one workspace, and then suddenly flips to display the count of another workspace.

See https://github.com/microsoft/pyrx/blob/6c8650bfe6bd61aa69cc93b35af8f78bff1e3115/packages/pyright/packages/pyright-internal/src/languageServerBase.ts#L1276, each workspace can start its own progressMessage.