Do not sync Variables pane for a Data Explorer "editor"

[juliasilge]

Addresses #7539

When a user opens the Data Explorer from a notebook's Variables pane, the Variables pane would incorrectly switch to the foreground console session instead of staying on the notebook session. This happened because the _syncToActiveEditor() method thought the Data Explorer "editor" was just a regular old editor, causing it to fall through to the default behavior of switching to the foreground console session.

This PR makes the Data Explorer "transparent" to session following; when a Data Explorer editor becomes active, the Variables pane now stays on whichever session it was showing. This preserves the context for users working in a notebook.

Release Notes

New Features

• N/A

Bug Fixes

• Fixed Variables pane navigating away from the correct notebook session when opening the Data Explorer (Variables pane navigates away from correct session when opening data viewer #7539)

QA Notes

@:variables @:data-explorer @:notebooks

1. Open a Jupyter notebook
2. Create a dataframe:

import pandas as pd
df = pd.DataFrame({"a": [1, 2, 3]})

3. Execute the cell
4. In the Variables pane, verify the session shows the notebook name
5. Click the data viewer icon on the df variable to open it
6. Verify the Variables pane still shows the notebook session (not the console)

[github-actions]

E2E Tests 🚀
This PR will run tests tagged with: @:critical @:variables @:data-explorer @:notebooks

^{readme  valid tags}

[juliasilge]

This test runs with the legacy notebook editor, which I think is fine for now. The fix applies to both notebook types since it's in the Variables service.

[nstrayer]

Looks good to me.

I do think we're approaching a point in this conditional logic where we want to white-list when we do switch rather than decide when we dont.

For example if you switch from a quarto doc to the settings pane right now it will change the variables, which feels a bit odd. Out of scope for this PR but a future note.