Alerting: Allow specifying uid for new rules added to groups (#99858)

When modifying rule groups the `uid` can be specified but only if the rule already existed in the DB. If the rule is new the update would be rejected.

This updates the RuleGroup provisioning apis to allow specifying the `uid` when creating/updating rule groups. 

Additionally, the RuleGroupIdx was not being updated when rules were reordered in the group.

Context: https://github.com/grafana/terraform-provider-grafana/pull/1971#issuecomment-2599223897
Relates to: https://github.com/grafana/terraform-provider-grafana/issues/1928

Fixes: #98283

pkg/tests/api/alerting/testing.go

@@ -687,6 +687,30 @@ func (a apiClient) ExportRulesWithStatus(t *testing.T, params *apimodels.AlertRu
 	return resp.StatusCode, string(b)
 }
 
+func (a apiClient) GetRuleGroupProvisioning(t *testing.T, folderUID string, groupName string) (apimodels.AlertRuleGroup, int, string) {
+	t.Helper()
+
+	req, err := http.NewRequest(http.MethodGet, fmt.Sprintf("%s/api/v1/provisioning/folder/%s/rule-groups/%s", a.url, folderUID, groupName), nil)
+	require.NoError(t, err)
+
+	return sendRequest[apimodels.AlertRuleGroup](t, req, http.StatusOK)
+}
+
+func (a apiClient) CreateOrUpdateRuleGroupProvisioning(t *testing.T, group apimodels.AlertRuleGroup) (apimodels.AlertRuleGroup, int, string) {
+	t.Helper()
+
+	buf := bytes.Buffer{}
+	enc := json.NewEncoder(&buf)
+	err := enc.Encode(group)
+	require.NoError(t, err)
+
+	req, err := http.NewRequest(http.MethodPut, fmt.Sprintf("%s/api/v1/provisioning/folder/%s/rule-groups/%s", a.url, group.FolderUID, group.Title), &buf)
+	require.NoError(t, err)
+	req.Header.Add("Content-Type", "application/json")
+
+	return sendRequest[apimodels.AlertRuleGroup](t, req, http.StatusOK)
+}
+
 func (a apiClient) SubmitRuleForBacktesting(t *testing.T, config apimodels.BacktestConfig) (int, string) {
 	t.Helper()
 	buf := bytes.Buffer{}