Bug 31219: Prevent JS injection in patron extended attributes

Bug 31219: Prevent JS injection in patron extended attributes

We are sanitizing other attributes but "extended patron attributes".

Test plan:
Make a patron attribute editable at the OPAC
Edit an existing patron, or register a new one
Use a script tag in the new value ("<script>alert("booh!")</script>" for
instance)
With this patch the value is remove if containing an HTML tag that is
not br b i em big small strong (see C4::Scrubber)

Signed-off-by: Mark Hofstetter <koha@trust-box.at>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>