fix: ongeki more resilient db migrations

src/main/resources/db/120/V1000_89__ongeki_event_map_unique.sql

@@ -1,3 +1,10 @@
+-- should have been not nullable in the first place smh
+DELETE FROM ongeki_user_event_map
+WHERE user_id IS NULL;
+
+ALTER TABLE ongeki_user_event_map
+    MODIFY user_id BIGINT NOT NULL;
+
 -- dedupe before adding new constraint just in case
 DELETE FROM ongeki_user_event_map
 WHERE id NOT IN (

src/main/resources/db/120/V1000_90__ongeki_event_music_level_unique.sql

@@ -1,7 +1,13 @@
 -- allow separate Technical Challenge records for each chart difficulty
 -- drop the old constraint and dedupe with the new constraint just in case again
 ALTER TABLE ongeki_user_event_music
-    DROP INDEX UKo5PU3BgZeTKB8SNykq9U7xjfshp;
+    DROP INDEX IF EXISTS UKo5PU3BgZeTKB8SNykq9U7xjfshp;
+
+DELETE FROM ongeki_user_event_music
+WHERE user_id IS NULL;
+
+ALTER TABLE ongeki_user_event_music
+    MODIFY user_id BIGINT NOT NULL;
 
 DELETE FROM ongeki_user_event_music
 WHERE id NOT IN (