Require the 'from' parameter for /notifications be an integer (#17283)

Co-authored-by: Erik Johnston <erikj@element.io>

tests/module_api/test_api.py

@@ -688,7 +688,7 @@ class ModuleApiTestCase(BaseModuleApiTestCase):
 
         channel = self.make_request(
             "GET",
-            "/notifications?from=",
+            "/notifications",
             access_token=tok,
         )
         self.assertEqual(channel.code, 200, channel.result)