Description of problem:

This issue is created to fix currently found bugs introduced by PF5 migration of the plugin:
 1. Webhooks edit modal shows values of previously opened modal.
 2. Webhooks edit modal doesn't update password.
 3. Webhooks edit modal submission causes unexpected and unnecessary API calls.

How reproducible:

Always

Is this issue a regression from an earlier version:

Yes

Steps to Reproduce:

• Navigate Administer > Webhook > Webhooks

1.    
    - Open any webhook (webhook-1) for editing
    - Close webhook-1
    - Open any other webhook (webhook-2) for editing
    - Observer values from webhook-1 instead of webhook-2 values

2.
    - Open any webhook with password for editing
    - Click Credentials
    - Change the password
    - Click submit
    - Check that webhook has old password value (you can do it via rails console, doesn't matter) in the DB

3.
     - Open any webhook for editing
     - Click submit
     - Observer 5 API calls instead of 2

Actual behavior:
1. Currently opened webhook contains values of previously opened webhook
2. After a user changes webhook password, it doesn't being changed
3. Webhook edit submition makes GET /api/v2/webhooks/events, GET /api/v2/webhooks/id and GET /api/v2/webhook_templates API calls along with PUT /api/v2/webhooks/id and GET /api/v2/webhooks (total 5)

Expected behavior:
1. Currently opened webhook must show it's own values regardless previously opened webhooks.
2. A user must be able to change password for a webhook, and the new value must persist.
3. Submition of a webhook editing must not trigger additional calls except for 1 to update the values (PUT /api/v2/webhooks/id) and 1 to refresh the table (GET /api/v2/webhooks)

Business Impact / Additional info: