fix files_external storage id migration
test files external amazon s3 storage id migration
on xp'ed mode and switching configurations: save raw mode instead of toggling filter mode in tabs since their status is unknown and dealt with by the Wizard. Fixes #11848

Backport of 8a48b088ed22f23f961da3c0eb9591989f8cc98a from master
Merge pull request #11614 from owncloud/fix_files_external_s3_storage_id_migration

fix files_external storage id migration
Merge branch 'stable7-upstream' into stable7-rotdrop