Bug: Profile Extensions UI incorrectly displays extensions after switching source under that profile.

[taramakage]

Does this issue occur when all extensions are disabled?: No

• VS Code Version: 1.101.0-dfaf44141ea9deb3b4096f7cd6d24e00c147a4b1-arm64
• OS Version: MacOS Darwin 24.5.0

Prerequisites:

• A list of VSCode profiles exists: Default, Rust, Python, etc.
• All these profiles are duplicated from Dufault and has their specific extensions.
• For example, Rust profile has rust-analyzer.

Steps to Reproduce:

1. Open VSCode with the Rust profile active and navigate to the Profiles settings UI.

2. Expand the Extensions list. It shows the extensions on Rust source correctly.

3. Switch to the Default source. The Extensions list for the Default source incorrectly includes extensions that are specific to the Rust source (e.g., rust-analyzer appears).

4. Switch back to the Rust source. The Extensions list for the Rust source now fails to display its own specific extensions (e.g., rust-analyzer disappeared).

5. Switch to the Python profile, then switch back to the Rust profile. The Extensions list for the Rust source now displays correctly again.

6. If steps 3 and 4 are repeated, The incorrect behavior reliably reoccurs.

Expected Behavior:

When switching between sources of a profile in the Profiles settings UI, the Extensions list should accurately display only the extensions configured for the selected source.

Additional Context:

This seems to be just a display bug; the extensions themselves load correctly during use.