URL encodes member user names when passing information for public access setting such that those with user names as emails containing a plus will be included in the rule

[AndyButland]

Prerequisites

• I have added steps to test this contribution in the description below

Fixes: #15723

Description

Resolves the linked issue by URL encoding the provided user names.

To Test:

• Create a member with a plus sign in the login name:

• Use the member when setting up a public access rule on a content item, and restricting access to specific members.
• Note that the member is now correctly saved to the rule.