Standalone - remove role from users on deletion

[wmortada]

Overview

When deleting a user role, this role should be removed from all users that have the role.

Before

When a role is deleted, users with this role still have the role.

After

When a role is deleted, it is also removed from all users with the role.

Comments

I've included an commit from @colemanw to avoid merge conflicts. This PR should be merged after #28422.

[civibot]

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[wmortada]

@artfulrobot another one for you to review.

[artfulrobot]

Will r-run it tomorrow. Night!

[wmortada]

Rebased to resolve merge conflict.

[artfulrobot]

I tested this by adding 2 roles to a user, deleting one of the roles. The user record was left with just the one role.

Looks great. Merging.