Alerting: Correctly escape provisioning API exports (#99039)

When exporting contact-points, mute-timings, and notification policies in the provisioning API, we need to escape the `$` character which is used in interpolation by file provisioning.

Follow up to #97985

pkg/tests/api/alerting/testing.go

@@ -839,6 +839,32 @@ func (a apiClient) DeleteMuteTimingWithStatus(t *testing.T, name string) (int, s
 	return resp.StatusCode, string(body)
 }
 
+func (a apiClient) ExportMuteTiming(t *testing.T, name string, format string) string {
+	t.Helper()
+
+	u, err := url.Parse(fmt.Sprintf("%s/api/v1/provisioning/mute-timings/%s/export", a.url, name))
+	require.NoError(t, err)
+	q := url.Values{}
+	q.Set("format", format)
+	u.RawQuery = q.Encode()
+
+	req, err := http.NewRequest(http.MethodGet, u.String(), nil)
+	require.NoError(t, err)
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	require.NoError(t, err)
+
+	defer func() {
+		_ = resp.Body.Close()
+	}()
+	body, err := io.ReadAll(resp.Body)
+	require.NoError(t, err)
+
+	requireStatusCode(t, http.StatusOK, resp.StatusCode, string(body))
+	return string(body)
+}
+
 func (a apiClient) GetRouteWithStatus(t *testing.T) (apimodels.Route, int, string) {
 	t.Helper()
 
@@ -883,6 +909,32 @@ func (a apiClient) UpdateRouteWithStatus(t *testing.T, route apimodels.Route, no
 	return resp.StatusCode, string(body)
 }
 
+func (a apiClient) ExportNotificationPolicy(t *testing.T, format string) string {
+	t.Helper()
+
+	u, err := url.Parse(fmt.Sprintf("%s/api/v1/provisioning/policies/export", a.url))
+	require.NoError(t, err)
+	q := url.Values{}
+	q.Set("format", format)
+	u.RawQuery = q.Encode()
+
+	req, err := http.NewRequest(http.MethodGet, u.String(), nil)
+	require.NoError(t, err)
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	require.NoError(t, err)
+
+	defer func() {
+		_ = resp.Body.Close()
+	}()
+	body, err := io.ReadAll(resp.Body)
+	require.NoError(t, err)
+
+	requireStatusCode(t, http.StatusOK, resp.StatusCode, string(body))
+	return string(body)
+}
+
 func (a apiClient) UpdateRoute(t *testing.T, route apimodels.Route, noProvenance bool) {
 	t.Helper()
 	status, data := a.UpdateRouteWithStatus(t, route, noProvenance)