Review Axivion Scan results for QtNetwork and fix if needed

We now have a permanent server that is used to scan Qt products with the Axivion static analyzer: https://axivion-srv.ci.qt.io/ . For Qt 6 modules specifically, we check for the new Qt rule set.

Definition of Done

We will go through all scan results for QtNetwork as part of this task. Since QtCore has progressed somewhat, please be mindful of issues reported there already.

If issues are deemed fixable, they should be fixed in QtNetwork. False positives should be handled by either marking the code to suppress the failure case or (if the underlying rule) is not applicable to Qt be removed from the scanner setup. Active engagement with the Axivion team is encouraged.

This task has two purposes. We want to fix any scan results genuinely worth fixing and secondly, we want to verify/fine-tune the rule sets for Qt applicability as those will likely be adjusted to have the most suitable default configuration for Axivion's static analyzer when targeting Qt application developers.

The Axivion team is very interested in false positives regarding the new Qt specific rules before Annotations are done in code. They would like to fix rules and adjust configurations if possible.