Ensure migration 73 gets run (#15809)

A dummy version of this migration was added in a previous commit, but
the import was never added back. This fixes that.

Author: mcmire

app/store/migrations/index.ts

@@ -73,6 +73,7 @@ import migration69 from './069';
 import migration70 from './070';
 import migration71 from './071';
 import migration72 from './072';
+import migration73 from './073';
 import migration74 from './074';
 import migration75 from './075';
 import migration76 from './076';
@@ -166,6 +167,7 @@ export const migrationList: MigrationsList = {
   70: migration70,
   71: migration71,
   72: migration72,
+  73: migration73,
   74: migration74,
   75: migration75,
   76: migration76,