Ask for prerelease switch

[rchiodo]

This is a temporary fix to address comments made here:

microsoft/vscode#15756 (comment)

If an insider's user is not on the prerelease bits, we'll ask them to switch.

Message looks like so:

[rchiodo]

This requires this to be fixed first:
microsoft/vscode#139528.

I thought that was already working. Turns out it isn't finished yet.

[rchiodo]

microsoft/vscode#139528 was fixed yesterday. Reopening this.

[codecov-commenter]

Codecov Report

Merging #8657 (dd2be8a) into main (622aab5) will increase coverage by 0%.
The diff coverage is 78%.

@@           Coverage Diff           @@
##            main   #8657     +/-   ##
=======================================
  Coverage     71%     72%             
=======================================
  Files        382     385      +3     
  Lines      24523   25794   +1271     
  Branches    3767    4198    +431     
=======================================
+ Hits       17542   18609   +1067     
- Misses      5457    5606    +149     
- Partials    1524    1579     +55     

Impacted Files	Coverage Δ
src/client/datascience/prereleaseChecker.ts	73% <73%> (ø)
src/client/common/utils/localize.ts	96% <100%> (+<1%)	⬆️
src/client/datascience/serviceRegistry.ts	98% <100%> (+<1%)	⬆️
src/client/datascience/utils.ts	44% <0%> (-3%)	⬇️
...ence/notebook/intellisense/intellisenseProvider.ts	79% <0%> (-1%)	⬇️
src/client/debugger/jupyter/kernelDebugAdapter.ts	77% <0%> (-1%)	⬇️
src/client/common/types.ts	100% <0%> (ø)
src/client/datascience/constants.ts	100% <0%> (ø)
...ent/datascience/jupyter/pythonVariableRequester.ts	76% <0%> (ø)
src/client/datascience/delayedFutureExecute.ts	58% <0%> (ø)
... and 19 more