Clarify error message when study bucket is not found in upload

[znatty22]

This message is too cryptic for end users to understand

[gsantia]

@znatty22 Was there any more info provided by the user? For example, how can I recreate this?

[znatty22]

@gsantia I think this happens when a user tries to save a document to the study bucket and study bucket name is null. The study bucket name has a regex validator on it that checks the name follows a specific format.

[znatty22]

@gsantia I think I know where this is coming from. Its an exception thats raised by the boto s3 client which is why we can't find it anywhere in the code lol.

I think this issue will get resolved once we fix bucket setup bc the bucket name is not saved to the Study on creation since bucket setup fails. So I guess right now, if the bucket name is blank due to failed bucket setup it will try to create a new doc and save it to an invalid bucket. So let's see what happens once we test #790 in QA/prod