fix(Core/Petitions): re-key petition_sign on petition_id and fix type-filtered signature deletes (#26668)

data/sql/updates/pending_db_characters/rev_1784315136456725704.sql

@@ -0,0 +1,10 @@
+-- petition_sign kept its (petitionguid, playerguid) primary key when the
+-- petition_id schema stopped writing petitionguid: every row inserts with
+-- petitionguid = 0, so the key collapses to (0, playerguid) and a character
+-- can never hold more than one signature row overall (later signs fail
+-- silently with a duplicate key on the async insert).
+-- Re-key on (petition_id, playerguid) and drop the signature rows orphaned
+-- by the type-filtered deletes that no longer match (`type` is not written
+-- by the insert either).
+DELETE `ps` FROM `petition_sign` `ps` LEFT JOIN `petition` `p` ON `p`.`petition_id` = `ps`.`petition_id` WHERE `p`.`petition_id` IS NULL;
+ALTER TABLE `petition_sign` DROP PRIMARY KEY, ADD PRIMARY KEY (`petition_id`, `playerguid`), DROP INDEX `idx_petition_id_player`;