Fix TestAccGrantComplexMySQL8 to grant correct dynamic privileges

The test was checking for CONNECTION_ADMIN and FIREWALL_EXEMPT privileges,
but the configuration was only granting SELECT and UPDATE. This mismatch
caused the test to fail with "grant CONNECTION_ADMIN not found".

MySQL 8.0+ dynamic privileges like CONNECTION_ADMIN and FIREWALL_EXEMPT
must be granted globally (database = "*"), not on specific databases.

Updated the test configuration to:
- Grant CONNECTION_ADMIN and FIREWALL_EXEMPT (instead of SELECT, UPDATE)
- Use database = "*" for global privileges (instead of specific database)

Author: zph

mysql/resource_grant_test.go

@@ -904,8 +904,8 @@ resource "mysql_user" "test" {
 resource "mysql_grant" "test" {
   user       = "${mysql_user.test.user}"
   host       = "${mysql_user.test.host}"
-  database   = "${mysql_database.test.name}"
-  privileges = ["SELECT", "UPDATE"]
+  database   = "*"
+  privileges = ["CONNECTION_ADMIN", "FIREWALL_EXEMPT"]
 }
 `, dbName, dbName)
 }