Custom type rules were always considered to have content available,
even when their summary template produced empty output. This caused
reports to be created when custom rules returned nil or empty strings.

Now content_available? checks if the description contains any
non-whitespace characters for custom rules, matching the behavior
of title_present?.

Also removes unnecessary '|| false' from Regexp#match? calls since
match? already returns a boolean (true/false), never nil.

Changelog: fixed

Fix custom rule content_available? to check for non-empty description

See merge request !368



Merged-by: Kev Kloss <kkloss@gitlab.com>
Approved-by: Kev Kloss <kkloss@gitlab.com>
Co-authored-by: ddieulivol <ddieulivol@gitlab.com>

Release v1.49.0

See merge request !369



Merged-by: Kev Kloss <kkloss@gitlab.com>
Approved-by: Kev Kloss <kkloss@gitlab.com>
Co-authored-by: ddieulivol <ddieulivol@gitlab.com>