Extend the detection of connection lost in the PostgreSQL ExceptionConverter (#7010)

|      Q       |   A
|------------- | -----------
| Type         | improvement
| Fixed issues | 

#### Summary

In some cases I'm getting the following exception:
`Doctrine\DBAL\Exception\DriverException #7
An exception occurred while executing a query: SQLSTATE[HY000]: General
error: 7 server closed the connection unexpectedly
This probably means the server terminated abnormally before or while
processing the request. `

I think this exception should be converted to the ConnectionLost
exception.

Author: petaak

src/Driver/API/PostgreSQL/ExceptionConverter.php

@@ -78,7 +78,10 @@ public function convert(Exception $exception, ?Query $query): DriverException
                 return new ConnectionException($exception, $query);
         }
 
-        if (str_contains($exception->getMessage(), 'terminating connection')) {
+        if (
+            str_contains($exception->getMessage(), 'terminating connection')
+            || str_contains($exception->getMessage(), 'server closed the connection')
+        ) {
             return new ConnectionLost($exception, $query);
         }