test: Add e2e tests for cred setup on workflow editor (no-changelog) (#8245)

## Summary

Follow-up to https://github.com/n8n-io/n8n/pull/8240

Adds e2e tests for the template credential setup in workflow editor


## Related tickets and issues

https://linear.app/n8n/issue/ADO-1463/feature-enable-users-to-close-and-re-open-the-setup

cypress/composables/modals/workflow-credential-setup-modal.ts

@@ -0,0 +1,12 @@
+/**
+ * Getters
+ */
+
+export const getWorkflowCredentialsModal = () => cy.getByTestId('setup-workflow-credentials-modal');
+
+/**
+ * Actions
+ */
+
+export const closeModal = () =>
+	getWorkflowCredentialsModal().find("button[aria-label='Close this dialog']").click();