Storage: Watch tests (#85496)

* basic watch tests working

* refactor to read previous event within poller

* add watch test files

* cleanup

* watch tests passing

* debug cleanup

* special handling for canceled context

* cleanup

* fix wire

* fix sqlite_sequence cleanup issue

* move watch tests to integration, wait for provisioned dashboards

* handle context deadline exceeded and eof errors

* add comment about sleep

pkg/tests/api/dashboards/api_dashboards_test.go

@@ -168,6 +168,10 @@ providers:
 		Login:          "admin",
 	})
 
+	// give provisioner some time since we don't have a way to know when provisioning is complete
+	// TODO https://github.com/grafana/grafana/issues/85617
+	time.Sleep(1 * time.Second)
+
 	type errorResponseBody struct {
 		Message string `json:"message"`
 	}