Test that the persistence bug of Claws is documented correctly

People have been complaining about persistence bugs while setting up Claws Mail. This lead me to believe that the persistence bug documented in https://tails.boum.org/doc/anonymous_internet/claws_mail/persistence.bug/ might not be accurate.

It would be good to try to setup a Claws Mail accounting with persistence from scratch. Core Tails people have access to testing credentials in our internal Git repo that would be perfect for that.

Related issues

Related to #7694 (closed)
Related to #6263 (closed)
Related to #9303 (closed)
Related to #9161 (closed)

Original created by @sajolida on 9159 (Redmine)

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