Remove unused motifSettings code from cZ

As default information of the same type that is not an action is collapsed are and there's a pref to control collapsing actions of the same type. The motifSettings code is used for motifs that want to collapse everything down for consecutive information from a particular user regardless of the type of information. None of the motifs do this, so let's removed this code and simplify / tidy things around it.

[Approval Request Comment]
Regression caused by (bug #): n/a
User impact if declined: none
Testing completed (on m-c, etc.): 2.53.22pre
Risk to taking this patch (and alternatives if risky): low
String changes made by this patch: none

Comment on attachment 9488462 [details] [diff] [review]
1967073-irc-remove-motifsettings-25322.patch

LGTM r/a+

Pushed by frgrahl@gmx.net:
https://hg.mozilla.org/comm-central/rev/aac760e19c9c
Remove unused motifSettings code from cZ. r=frg DONTBUILD

https://gitlab.com/seamonkey-project/seamonkey-2.53-comm/-/commit/77caecd9a56a57acb160adb3b7b190d571e20b94
Remove unused motifSettings code from cZ. r=frg a=frg