Bugfix: Readonly user attributes have no effect on group memberships

[AlexAndBear]

Description

Related Issue

• Fixes https://github.com/owncloud/enterprise/issues/5941

Motivation and Context

How Has This Been Tested?

• test environment:
• test case 1:
• test case 2:
• ...

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests
• Documentation
• Maintenance (e.g. dependency updates or tooling)

Open tasks:

• ...

[sonarqubecloud]

Quality Gate failed

Failed conditions

70.0% Duplication on New Code (required ≤ 50%)

See analysis details on SonarCloud