Copilots can't set themselves as assignee and copilot *before* activation

[jmgasper]

REF: https://topcoder.atlassian.net/browse/PROD-4413

@suppermancool - We're seeing an issue with the latest change that is causing a problem in prod.

Expectation:

Copilots should be able to create a draft challenge with themselves as the assignee and copilot. If they are the assignee, the should not be allowed to activate or close the task.

If the task is active, but assigned to someone else, the copilot should not be able to assign it to themselves.

Currently:

In dev, login with TCConnCopilot, and attempt to create a new draft task with the copilot set to TCConnCopilot, and assignee set to TCConnCopilot with a payment of $1 for the copilot and the task prize.

You will see an error that says Please select a copilot, even though the copilot is set:

[suppermancool]

@jmgasper done in work-manager-issue-1580.patch (this patch against commit c0c393d in develop branch)

Actually, the fix in the below email caused that issue. The Save Draft button only shows before activation, but the requirement in that email is hiding Save Draft for Copilot assign themselves as assignee