[bp/r52166][FIX] cookie consent: Correct mistaken consent when using checkbox (not checked was ignored), make dialog mode modal and add an event to trigger custom js handlers on granting consent

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@52167 b456876b-0849-0410-b77d-98878d47e9d5
[SVN] Merge info failed to commit again [from revision 52166]

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@52168 b456876b-0849-0410-b77d-98878d47e9d5