AC-9755:Set default collation to utf8mb4 for MySQL

Author: glo17680

dev/tests/setup-integration/_files/Magento/TestSetupDeclarationModule1/fixture/declarative_installer/rollback.mysql829.php

@@ -21,7 +21,7 @@
     ],
     'after' => [
         'store' => 'CREATE TABLE `store` (
-  `store_owner` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT \'Store Owner Name\'
+  `store_owner` varchar(255) COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT \'Store Owner Name\'
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci'
     ]
 ];

dev/tests/setup-integration/_files/Magento/TestSetupDeclarationModule2/fixture/shards.mysql829.php

@@ -8,12 +8,12 @@
 return [
     'test_table_one' => 'CREATE TABLE `test_table_one` (
   `smallint` smallint NOT NULL AUTO_INCREMENT,
-  `varchar` varchar(254) COLLATE utf8mb4_general_ci DEFAULT NULL,
+  `varchar` varchar(254) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL,
   PRIMARY KEY (`smallint`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci',
     'test_table_two' => 'CREATE TABLE `test_table_two` (
   `smallint` smallint NOT NULL AUTO_INCREMENT,
-  `varchar` varchar(254) COLLATE utf8mb4_general_ci DEFAULT NULL,
+  `varchar` varchar(254) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL,
   PRIMARY KEY (`smallint`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci',
     'reference_table' => 'CREATE TABLE `reference_table` (