Bug 3831: Add a warning to about page when there is no FA framework

Bug 3831: Add a warning to about page when there is no FA framework

The feature is effectively disab;ed throughout Koha when this framework
is deleted. There do not appear to be any other side effects.

We should report this on the about page for informatinal purposes

To test:
1 - Apply patch
2 - Check about page, no change
3 - sudo koha-mysql kohadev
    UPDATE biblio_framework SET frameworkcode = 'FB' WHERE
    frameworkcode = 'FA'
4 - Refresh about page
5 - Note new warning
6 - sudo koha-mysql kohadev
    UPDATE biblio_framework SET frameworkcode = 'FA' WHERE
    frameworkcode = 'FB'
7 - Refresh about page
8 - No warning

Signed-off-by: Phil Ringnalda <phil@chetcolibrary.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>