The MariaDB version 10.6 doesn't seem supported with current Nextcloud
versions and the test fails with the following error[1]:
nextcloud # [ 14.950034] nextcloud-setup-start[1001]: Error while trying to initialise the database: An exception occurred while executing a query: SQLSTATE[HY000]: General error: 4047 InnoDB refuses to write tables with ROW_FORMAT=COMPRESSED or KEY_BLOCK_SIZE.
According to a support-thread in upstream's Discourse[2] this is because
of a missing support so far.
Considering that we haven't received any bugreports so far - even though
the issue already exists on master - and the workaround[3] appears to
work fine, an evaluation warning for administrators should be
sufficient.
[1] https://hydra.nixos.org/build/155015223
[2] https://help.nextcloud.com/t/update-to-next-cloud-21-0-2-has-get-an-error/117028/15
[3] setting `innodb_read_only_compressed=0`