[Investigate] Why can't `ms-python.python` be installed from OpenVSX

MR: Pending

Description

We should figure out why the Web IDE won't install extensions that seem to be available (like ms-python.python).

• This is probably something to do with "composite extensions" (not the right term but it's a pack of extensions)

Acceptance Criteria

• Investigation complete and implementation plan for resolving this issue is made.
• Is this the same issue as gitlab#463876