Cannot remove all roles of an user from site memberships

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.2.X
• Fix Version/s: 7.2.X
• Component/s: Collaboration > Item Selector, User Management
• Labels:
  • 7.2.x-only
  • ee-ts
• Branch Version/s:
  7.2.x
• Backported to Branch:
  Committed
• Story Points: 1
• Fix Priority: 4
• Git Pull Request: https://github.com/liferay/liferay-portal-ee/pull/18049

Steps to reproduce:

1. In Liferay DXP site go to People -> Membership_s, _Users tab.
2. Click Add button and select a existing user to become a member of the site.
3. Click on the three dots of this new user -> Assign new site Roles, and select Site Administrator role. Click 'Done'.
4. Click again on Assign new site Roles for this user and unselect Site Administrator. Click 'Done'

Expected result: After saving, no site roles are assigned to the user.

Current result: 'Done' button is disabled. If there is no role selected, 'Done' button is always disable, so you cannot remove all roles from a user from this option.

Important notes:

• Not reproducible in master.
• After applying LPS-104263 to 7.2.x, the behaviour is the expected.