Remove access without account

[MrFlashAccount]

Pull Request Description

Closes: https://github.com/enso-org/cloud-v2/issues/1229

This PR removes button "Continue without creating an account" on Login page.
Aslo, This PR removes weird behaivor when dashboard goes into offline mode in canse if network error is happening

Important Notes

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• The documentation has been updated, if necessary.
• Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• All code follows the
  Scala,
  Java,
  TypeScript,
  and
  Rust
  style guides. In case you are using a language not listed above, follow the Rust style guide.
• Unit tests have been written where possible.

[somebody1234]

QA ✅

• ✅ "use app without account" button is gone
• ✅ doesn't assume cloud backend is unreachable if network error occurs
• ✅ local backend still seems to work even if Cognito is unreachable (disabled through network devtools tab). not sure how it's working but it looks like it is working...? maybe it's fine as long as the token is not expired. further testing SHOULD be done to find out what happens when the Cognito access token (if it has one) is expired.