Attempt other auth flow if sharedkey is invalid #251
Description
Ref. case https://equinor.slack.com/archives/CT986DYF3/p1769596454265799 where user upload failed due to sharedkey that was invalid. (Signed by previous version of Sumo-core and could not be validated by the new due to new set of keys)
Related issue: equinor/fmu-sumo-sim2sumo#192
We should:
If sharedkey validation fails: try to authorize with some other mechanism (fallback)
If that also fails: fail as normal
To decide:
Are there some cases/error codes where we do not need to try another method?
Or should we just always try a fallback if sharedkey fails? I.e. treat the sharedkey as a "bonus"