Return ajv errors from validate method.

packages/declaform/tests/declaform.test.ts

@@ -152,8 +152,7 @@ describe('Declaform', () => {
         await form.ready;
         const isValid = await form.validate();
 
-        expect(isValid).toBe(false);
-
+        expect(isValid).not.toBe(true);
     });
 });