Prevent ACL admins to remove themselves

[vcastellm]

Description

This PR implements a protection to ACLs so going forward an admin can not remove himself from the admins list, it should be removed by another admin.

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually

[QEDK]

This PR implements a protection to ACLs so going forward an admin can not remove himself from the admins list, it should be removed by another admin.

The admin should not be able to remove themselves when there's only one admin, otherwise I think they should be able to remove themselves, no?

[Stefan-Ethernal]

As a side note, @QEDK's comment makes sense as well.

[vcastellm]

The admin should not be able to remove themselves when there's only one admin, otherwise I think they should be able to remove themselves, no?

We can not count how many admins there are in the lists due to limitation of the state. This was the first idea but we needed to adapt it to this.