Remove placeholder in Container Registry cleanup policy text field

Problem: placeholder

The .* placeholder in the container registry is confusing because users are not noticing it is a placeholder and/or not knowing what it will do. "I was too scared to try the cleanup policy because I don't know what it will do."

In checking one of my projects, the .* is not a placeholder, but is pre-filled text. We should not pre-fill text on behalf of the user.

Problem: validation toast

If the user does not fill in a value, there should not be an error. The fields are not mandatory. If there is an error associated with the text input, display it under the text input rather than as a toast.

Proposal

Proposal	Notes
	Remove placeholder or pre-filling .*
no image	If the user does not fill in a value for keep or remove tags matching, there should not be an error.
	If there is an error associated with the text input, display it under the text input rather than as a toast.