[conf](test) Add max_bucket_num_per_partition config to regression test configurations

Configure max_bucket_num_per_partition in regression test configs for testing.

Author: gavinchou

regression-test/pipeline/cloud_p0/conf/fe_custom.conf

@@ -48,4 +48,5 @@ enable_advance_next_id = true
 check_table_lock_leaky = true
 enable_outfile_to_local=true
 
-enable_notify_be_after_load_txn_commit=true
+enable_notify_be_after_load_txn_commit=true
+max_bucket_num_per_partition=512

regression-test/pipeline/p0/conf/fe.conf

@@ -91,4 +91,5 @@ force_olap_table_replication_allocation=tag.location.default:1
 max_query_profile_num = 2000
 max_spilled_profile_num = 2000
 
-check_table_lock_leaky=true
+check_table_lock_leaky=true
+max_bucket_num_per_partition=512