[MM-36472] Fix inconsistencies in Roles columns (#18390)

* Fix inconsistencies in Roles columns

* Add new migrations

scripts/mattermost-postgresql-6.0.sql

@@ -73,7 +73,7 @@ ALTER TABLE public.channelmemberhistory OWNER TO mmuser;
 CREATE TABLE public.channelmembers (
     channelid character varying(26) NOT NULL,
     userid character varying(26) NOT NULL,
-    roles character varying(64),
+    roles character varying(256),
     lastviewedat bigint,
     msgcount bigint,
     mentioncount bigint,
@@ -675,7 +675,7 @@ CREATE TABLE public.sessions (
     lastactivityat bigint,
     userid character varying(26),
     deviceid character varying(512),
-    roles character varying(64),
+    roles character varying(256),
     isoauth boolean,
     expirednotify boolean,
     props jsonb
@@ -825,7 +825,7 @@ ALTER TABLE public.systems OWNER TO mmuser;
 CREATE TABLE public.teammembers (
     teamid character varying(26) NOT NULL,
     userid character varying(26) NOT NULL,
-    roles character varying(64),
+    roles character varying(256),
     deleteat bigint,
     schemeuser boolean,
     schemeadmin boolean,