Remove PDO rethrow

The PDOException was rethrown in general.php so that it could be caught
in the catch block of http.php. However, [a change in
utopia-php/framework](9d37326851)
caused the exception to be masked as an Exception rather than the
underlying PDOException. As such, the `$th instanceof PDOException` in
http.php is always false and `$db = null` is never executed. Since these
snippets of code aren't doing anything or adding value, they should be
removed.

In addition, the `$db = null` may have been added to ensure the
connection was added back to the pool and/or reset if needed, but it
seems like that's not a problem anymore.

app/controllers/general.php

@@ -403,11 +403,6 @@ App::error()
         $version = App::getEnv('_APP_VERSION', 'UNKNOWN');
         $route = $utopia->match($request);
 
-        /** Delegate PDO exceptions to the global handler so the database connection can be returned to the pool */
-        if ($error instanceof PDOException) {
-            throw $error;
-        }
-
         if ($logger) {
             if ($error->getCode() >= 500 || $error->getCode() === 0) {
                 try {

app/http.php

@@ -317,13 +317,6 @@ $http->on('request', function (SwooleRequest $swooleRequest, SwooleResponse $swo
         Console::error('[Error] File: ' . $th->getFile());
         Console::error('[Error] Line: ' . $th->getLine());
 
-        /**
-         * Reset Database connection if PDOException was thrown.
-         */
-        if ($th instanceof PDOException) {
-            $db = null;
-        }
-
         $swooleResponse->setStatusCode(500);
 
         $output = ((App::isDevelopment())) ? [