MM-54123 Add group to channel (#22954)

* adding group members to channel initial commit

* adding group to channel functionality along with add new team members

* fixing circular dependency

* fixing e2e and other optimizations

* adding e2e tests for adding group members to channels

* cypress lint

* fixing comments

* adding count to button

* improvements

* adjusting some stuff from PR comments

* remove ability to add user to team, update message for non-team members

* remove adding to team from add groups functionality

* update misspelled variable

* lint and unit test fixes

* add tests, cleanup

* lint fix

* revert package-lock.json

* fixes for cypress tests

* rename TeamInviteBanner to TeamWarningBanner, since invites are no longer allowed

* update for warning

* lint fixes

* cleanup

* fix failing e2e tests

* update messages to not use markdown

---------

Co-authored-by: Scott Bishel <scott.bishel@mattermost.com>
Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/group.go

@@ -24,6 +24,17 @@ func (a *App) GetGroup(id string, opts *model.GetGroupOpts, viewRestrictions *mo
 		}
 	}
 
+	if opts != nil && opts.IncludeMemberIDs {
+		users, err := a.Srv().Store().Group().GetMemberUsers(id)
+		if err != nil {
+			return nil, model.NewAppError("GetGroup", "app.member_count", nil, "", http.StatusInternalServerError).Wrap(err)
+		}
+
+		for _, user := range users {
+			group.MemberIDs = append(group.MemberIDs, user.Id)
+		}
+	}
+
 	if opts != nil && opts.IncludeMemberCount {
 		memberCount, err := a.Srv().Store().Group().GetMemberCountWithRestrictions(id, viewRestrictions)
 		if err != nil {
@@ -636,6 +647,19 @@ func (a *App) GetGroups(page, perPage int, opts model.GroupSearchOpts, viewRestr
 		return nil, model.NewAppError("GetGroups", "app.select_error", nil, "", http.StatusInternalServerError).Wrap(err)
 	}
 
+	if opts.IncludeMemberIDs {
+		for _, group := range groups {
+			users, err := a.Srv().Store().Group().GetMemberUsers(group.Id)
+			if err != nil {
+				return nil, model.NewAppError("GetGroup", "app.member_count", nil, "", http.StatusInternalServerError).Wrap(err)
+			}
+
+			for _, user := range users {
+				group.MemberIDs = append(group.MemberIDs, user.Id)
+			}
+		}
+	}
+
 	return groups, nil
 }