…nd adding initial control tests.

…ontrols

Adding mocks for apiFetch in the edit tests
Using zero values for default input[type=number] fields to receive more reliable userEvent.type results

…bute to submitButtonText.

To determine whether deprecation v1 is eligible we need to check for both the old property subscribeButton and its value since only checking for empty matches empty/default on other versions.

See: #18993#issuecomment-793490858

…ributes

 Bring all deprecations and fixtures into line

Clearing some controls before modifying values

…porarily to avoid type/import errors that should be fixed when we update the wordpress monorepo