fix(DB/pool): remove redundant Meshlok creature pool (#6779)

Pool id 1211 is redundant and it needlessly reduces the spawn chance of Meshlok.
Rare creature spawn chance should be handled exclusively by SAI

- Closes #6745
- Closes https://github.com/chromiecraft/chromiecraft/issues/1098

Fix by @T1ti

data/sql/updates/pending_db_world/rev_1625601630306437708.sql

@@ -0,0 +1,4 @@
+INSERT INTO `version_db_world` (`sql_rev`) VALUES ('1625601630306437708');
+
+DELETE FROM `pool_creature` WHERE  `pool_entry`=1211;
+DELETE FROM `pool_template` WHERE  `entry`=1211;