Integration tests failing on linux using vscode 1.78.0

[aeisenberg]

We are hitting this issue microsoft/vscode#181527 for all of our integration tests running on linux. Temporary solution is to roll back to vscode v1.77.3 until this is fixed.

[aeisenberg]

cc: @github/code-scanning-secexp-reviewers

We are still blocked on removing the workaround, but looks like the linked issue has a target date of end of August for a fix, so let's keep an eye on this and revert #2403.

[aeisenberg]

Revert commit is here: #2998

[aeisenberg]

Already fixed in #2877. Somehow even though microsoft/vscode#181527 is not fixed, we are able to run linux integration tests against stable.