[MM-23017] Add check for groups to SendNotifications (#14039)

* MM-23017 Check group mentions as part of notification logic

* Add nil groups to existing test cases

* MM-23017 Add tests for insertGroupMention and addGroupMention

* MM-23017 Add tests for getExplicitMentions that have groups

* Add tests for group store GetMemberUsersNotInChannel

* MM-23017 Add tests for AllowGroupMentions

* MM-23017 Fix error message name

* MM-23017 Swap Checks to Name

* MM-23017 Code review fixes

* Rename var and fix allowGroupMentions test

* MM-23017 Use GetMemberUsersInTeam inside of insertGroupMentions

* MM-23017 use group mentions permission

* Actually call GetMemberUsersInTeam

* Remove unnecessary new line

* Uncomment filter allow reference

* MM-23017 Fix group channel notifications

* Update store layer

* MM-23017 Improve test coverage for group channels

* Trigger CI

* Trigger CI

app/post.go

@@ -1230,7 +1230,7 @@ func isPostMention(user *model.User, post *model.Post, keywords map[string][]str
 	}
 
 	// Check for keyword mentions
-	mentions := getExplicitMentions(post, keywords)
+	mentions := getExplicitMentions(post, keywords, make(map[string]*model.Group))
 	if _, ok := mentions.Mentions[user.Id]; ok {
 		return true
 	}