Added 'includeSystem' parameter to loadAllGroups and related methods

[mikadamczyk]

🎫 Issue	N/A

Related PRs:

• Added support for including system content type groups in ContentTypeController rest#208

Description:

• Added optional includeSystem flag to ContentTypeService::loadContentTypeGroups (contracts, decorators, siteaccess-aware) and wired it through persistence/cache/gateway so system groups can be fetched while keeping the default non-system filter.
• Updated Doctrine gateway to skip is_system filter when includeSystem=true; cache handler now maintains separate keys for lists with/without system groups and invalidates both on create/update/delete.
• Added integration coverage for system-group inclusion and adjusted cache tests to reflect new keys/signatures.

For QA:

Documentation:

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud