Removes deprecated config option (#21538)

Author: adamsong

config/dbconfig.txt

@@ -12,7 +12,7 @@ ASYNC_QUERY_TIMEOUT 10
 BLOCKING_QUERY_TIMEOUT 5
 
 ## The maximum number of additional threads BSQL is allowed to run at once
-BSQL_THREAD_LIMIT 50
+POOLING_MAX_SQL_CONNECTIONS 50
 
 ## Uncomment to enable verbose BSQL communication logs
 #BSQL_DEBUG