chg: [schema] Sightings UUID column should be unique

INSTALL/MYSQL.sql

@@ -1109,7 +1109,7 @@ CREATE TABLE IF NOT EXISTS `sightings` (
   INDEX `attribute_id` (`attribute_id`),
   INDEX `event_id` (`event_id`),
   INDEX `org_id` (`org_id`),
-  INDEX `uuid` (`uuid`),
+  UNIQUE INDEX `uuid` (`uuid`),
   INDEX `source` (`source`),
   INDEX `type` (`type`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

db_schema.json

@@ -8115,7 +8115,7 @@
             "attribute_id": false,
             "event_id": false,
             "org_id": false,
-            "uuid": false,
+            "uuid": true,
             "source": false,
             "type": false
         },