Your database is not configured correctly. Seams like either you or your host has set Innodb to its minimum settings instead of its default settings. Contact your host and ensure they've the following configured.
innodb_file_format=Barracuda;
innodb_file_per_table=ON;
innodb_large_prefix=1;
If they are configured ensure your database tables have ROW_FORMAT set to DYNAMIC.
Have also added a feature ticket to check if we're still indexing varchar(255) columns without lengths.
forge.joomlapolis.com/issues/8852