Duplicate toasts from notebook format on save

[bamurtaugh]

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

• VS Code Version:
  Version: 1.78.0-insider (user setup)
  Commit: 3e0b354
  Date: 2023-04-06T05:20:25.265Z
  Electron: 22.4.3
  Chromium: 108.0.5359.215
  Node.js: 16.17.1
  V8: 10.8.168.25-electron.0
  OS: Windows_NT x64 10.0.25330
  Sandboxed: Yes
• OS Version: Windows 11

Steps to Reproduce:

1. Enable the setting Notebook › Format On Save with latest Python (v2023.7.10961009) and Jupyter (v2023.4.1000961023) pre-releases
2. ctrl+s in a notebook
3. Receive what appear to be duplicate notifications

[rebornix]

@brettcannon do you have ideas if there is anything we can do in the core to improve this or it should be improved in Python extension?

[brettcannon]

The second prompt is to nudge folks to migrate to our new autopep8 extension (I believe that's an experiment that's now hit 100% of users, right, @luabud ?). So the latter one is on its way out (my guess is next iteration if telemetry suggests it makes sense).

[luabud]

we haven't hit 100% for the formatting notification as we just started it (we hit 100% for the linting ones). Agreed that provided things look good we could deprecate the first one in favour of the second (cc @karthiknadig)

[luabud]

transferring to the Python extension repo just to make sure it's on our radar for the next iteration