Make uploads migration task handle all uploads instead of a hardcoded list

What does this MR do and why?

Changes the gitlab:uploads:migrate:all and gitlab:uploads:migrate_to_local:all Rake tasks so that they iterate over all uploads in the DB instead of using a hardcoded list of upload types.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.

Related to #23593 (closed)