Update Drupal core from 9.1.4 to 9.1.5 ( ~9.1 ) and remove committed patches

Problem/Motivation

Drupal 9.1.5 was released 4 Mar 2021 at 16:41 EET
https://www.drupal.org/project/drupal/releases/9.1.5

Proposed resolution

Remove committed patches to allow the update to Drupal 9.1.5
#3128548: Add optional parameters to StatementInterface::fetchObject() to be in line with the PDO implementation of the method fetchObject()