bandaid to resolve #10651 (#10718)

When multiple instances run migrations race conditions are encountered that result in exceptions getting thrown. We try to mitigate this using auto-retry. The code in this PR is one more instance where a race condition can cause an exception, and it gets mitigated with an auto-retry.

src/metabase/db.clj

@@ -211,10 +211,9 @@
     (if (has-unrun-migrations? liquibase)
       (do
         (log/info (trs "Migration lock is cleared. Running migrations..."))
-        (let [^Contexts contexts nil]
-          (.update liquibase contexts)))
+        (u/auto-retry 3 (let [^Contexts contexts nil] (.update liquibase contexts))))
       (log/info
-       (trs "Migration lock cleared, but nothing to do here! Migrations were finished by another instance.")))))
+        (trs "Migration lock cleared, but nothing to do here! Migrations were finished by another instance.")))))
 
 (defn- force-migrate-up-if-needed!
   "Force migrating up. This does two things differently from `migrate-up-if-needed!`: