Better UX for GitHub credential and timeout errors

[axosoft-ramint]

Currently, GitHub credentials errors and timeout errors pop up as annoying error notifications. The credential issue is related to 401s from GitHub queries, and the notification offers a "reauthenticate" option. But if it's a permissions problem or something, reauthenticating does not help. Even choosing to "hide notifications from GitLens" doesn't stop the notifications from popping up again the next time you load a window.

We need to surface these issues in a less invasive way and move away from the "error notification" pattern as it just creates friction for users, especially when using options like "reauthenticate" does not make the issue go away. We should still log them properly so that it can help us investigate when users have issues with integration features, but the UX needs to be improved.