[BUGFIX] Provide UpgradeWizard for outdated be_users uc settings

Backend users each have a serialized array of individual user
configuration, called "uc" persisted in the be_users table.
Before TYPO3 9.5, the structure of this configuration could sometimes
contain stdClass objects, which is no longer supported. Logging in as
a backend user with such an outdated "uc" array would then crash several
parts of the TYPO3 backend, because the BackendUserConfiguration class
will try to access an stdClass type configuration like an array.

An UpgradeWizard called "BackendUserConfigurationUpdate" is now
provided, which allows to update any outdated "uc" structure of all
backend users.

Resolves: #89269
Resolves: #89268
Resolves: #86398
Releases: master, 9.5
Change-Id: Ic2158b34e70c7f931f4ef8acc8c39af618e241e9
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61906


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Tested-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>