[BUGFIX] Fix broken icon for 'Federated States of Micronesia' in sys_language

If someone has 'Federated States of Micronesia' selected in "Select flag icon"
the value will become invalid after this patch is applied.
It has to be manually changed to "fm" by the editor.

Resolves: #81878
Releases: master, 8.7
Change-Id: Ia60e12138495ade51e4c45da1533ff3cc3826d06
Reviewed-on: https://review.typo3.org/53511


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>