Is your feature request related to a problem? Please describe.
When deleting resources, it is currently not guaranteed that the PushSecrets will be deleted before the associated SecretStores.

This problem can occur if, for example, you want to delete the namespace and thereby delete all the resources (PushSecrets and SecretStores) in it. It is a coincidence which resources are deleted first. If the SecretStore is deleted first, deleting the PushSecrets fails and cannot be done by Kubernetes. You have to delete it manually by hand.

This is a problem, especially if the deletion and creation of resources is to be done automatically - for example using frameworks such as Crossplane or Helm.

Describe the solution you'd like
Using a finalizer when the DeletionPolicy is Delete enables a controlled, successful removal of SecretStores and PushSecrets.
Such a solution would also help very well with the automated deletion of resources.