Invalidate cache on account update

[sergeibbb]

Issue 1. Cached values from the previous account

Steps to reproduce

• connect one GitHub account on GKDev
• sync account on GitLens, reload window, open launchpad -> you get this GitHub account cached
• go to GKDev disconnect GitHub and connect another account.
• sync accounts on GitLens, open launchpad

Expected result

• launchpad gets the new GitHub account as "currentAccount"

Current result

• launchpad gets the old cached GitHub account as "currentAccount"

Issue 2. swallowing of an Authentication Error

• connect GitLab account on GKDev
• sync account on GitLens
• revoke the GK application on GitLab
• reload VSCode window -> that makes the current account set to "undefined"
• open launchpad

Expected result:

• no PRs
• Auth error indication

Actual result:

• no error indication, just no PRs:
  

GitLens and VSCode

• GitLens: 17.9 -> pre-release: 2026.1.3004
• VSCode: 1.109.0-insider