Issue Summary

Unable to remove the 'Component lead' value even when the Default assignee is unassigned.
The Component Lead cannot be left empty in the UI if it has already been assigned.

Steps to Reproduce

1. Add 'Component lead' to a user from UI, and Default assignee is component lead.
   Component='TEST for Component Lead value'
   Component lead= <user name>
   Default assignee= Unassigned/componentLead
   
2. Now try to remove the 'Component lead' name from the component to keep it Empty.
3. Edit doesn't provide a way to make 'Component lead' field empty
   

Expected Results

'Component lead' field value should be removed.

Actual Results

'Component lead' field can't be set to Empty from UI.

Workaround

Use API to Update Component lead empty: https://developer.atlassian.com/cloud/jira/platform/rest/v3/api-group-project-components/#api-rest-api-3-component-id-put 

{    "leadAccountId": ""}