Cleaner exit when user credentials are incorrect

[craddm]

✅ Checklist

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🚦 Depends on

⤴️ Summary

When the user rejects the current credentials when asked to confirm they are correct, code would still continue to run, resulting in numerous additional, unnecessary and misleading error messages.

In addition, when the user rejects the Graph API credentials as incorrect, there is currently no clear way to change those credentials.
Graph API log-in is, unlike Az CLI log-in, not done by the user at the command line.

This PR simply exits when the user confirms that the credentials are incorrect, and prints only informative error messages.
In addition, it advises the user how to remove the cached Graph API credentials so as to be able to login with other credentials.

🌂 Related issues

Closes #2280
Closes #2153

🔬 Tests

Tested locally

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
data_safe_haven/exceptions
__init__.py
data_safe_haven/external/api
credentials.py					231-235
graph_api.py					840
Project Total

This report was generated by python-coverage-comment-action

[JimMadge]

I don't think this is how we should solve this. We want to catch the problem and raise a suitable exception, which is handled by the command function.

[JimMadge]

Example output

My own review

[JimMadge]

@craddm Could you take a look at this and say what you think?

I can't request a review from you as you opened the PR 😆

[craddm]

LGTM