Alerting: Provisioning GET routes for mute timings (#49044)

* Define GET routes and run codegen

* Wire up forked and non-generated API

* Implement and wire

* Tests, authorization

* Fix linter error

pkg/tests/api/alerting/api_provisioning_test.go

@@ -273,6 +273,50 @@ func TestProvisioning(t *testing.T) {
 			require.Equal(t, 200, resp.StatusCode)
 		})
 	})
+
+	t.Run("when provisioning mute timings", func(t *testing.T) {
+		url := fmt.Sprintf("http://%s/api/provisioning/mute-timings", grafanaListedAddr)
+
+		t.Run("un-authenticated GET should 401", func(t *testing.T) {
+			req := createTestRequest("GET", url, "", "")
+
+			resp, err := http.DefaultClient.Do(req)
+			require.NoError(t, err)
+			require.NoError(t, resp.Body.Close())
+
+			require.Equal(t, 401, resp.StatusCode)
+		})
+
+		t.Run("viewer GET should succeed", func(t *testing.T) {
+			req := createTestRequest("GET", url, "viewer", "")
+
+			resp, err := http.DefaultClient.Do(req)
+			require.NoError(t, err)
+			require.NoError(t, resp.Body.Close())
+
+			require.Equal(t, 200, resp.StatusCode)
+		})
+
+		t.Run("editor GET should succeed", func(t *testing.T) {
+			req := createTestRequest("GET", url, "editor", "")
+
+			resp, err := http.DefaultClient.Do(req)
+			require.NoError(t, err)
+			require.NoError(t, resp.Body.Close())
+
+			require.Equal(t, 200, resp.StatusCode)
+		})
+
+		t.Run("admin GET should succeed", func(t *testing.T) {
+			req := createTestRequest("GET", url, "admin", "")
+
+			resp, err := http.DefaultClient.Do(req)
+			require.NoError(t, err)
+			require.NoError(t, resp.Body.Close())
+
+			require.Equal(t, 200, resp.StatusCode)
+		})
+	})
 }
 
 func createTestRequest(method string, url string, user string, body string) *http.Request {