Bug 34684: Prevent 220600007.pl to fail if run twice

Bug 34684: Prevent 220600007.pl to fail if run twice

The error is
  ERROR 1292 (22007): Truncated incorrect DECIMAL value: 'no'

Happens on MariaDB 10.5.22, not MySQL 8

Test plan:
update systempreferences set value="0" where variable="DisplayClearScreenButton";
play installer/data/mysql/db_revs/220600007.pl
select value from systempreferences where variable="DisplayClearScreenButton";
=> "no"

update systempreferences set value="1" where variable="DisplayClearScreenButton";
play installer/data/mysql/db_revs/220600007.pl
select value from systempreferences where variable="DisplayClearScreenButton";
=> "issueslip"

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>