Folder API: optionally force deleting Grafana 8 alerts when deleting a folder (or error) (#36427)

* Folder API: Add an optional query parameter for allowing deleting a  folder containing rules

* Update frontend

- Set forceDeleteRules=true when frontend deletes a folder
- Improve modal text

* Update docs

* Apply suggestions from code review

Co-authored-by: gotjosh <josue@grafana.com>
Co-authored-by: Nathan Rodman <nathanrodman@gmail.com>
Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

public/app/features/folders/FolderSettingsPage.tsx

@@ -66,10 +66,11 @@ export class FolderSettingsPage extends PureComponent<Props, State> {
     evt.stopPropagation();
     evt.preventDefault();
 
+    const confirmationText = `Do you want to delete this folder and all its dashboards and alerts?`;
     appEvents.publish(
       new ShowConfirmModalEvent({
         title: 'Delete',
-        text: `Do you want to delete this folder and all its dashboards?`,
+        text: confirmationText,
         icon: 'trash-alt',
         yesText: 'Delete',
         onConfirm: () => {

public/app/features/folders/state/actions.ts

@@ -31,7 +31,7 @@ export function saveFolder(folder: FolderState): ThunkResult<void> {
 
 export function deleteFolder(uid: string): ThunkResult<void> {
   return async (dispatch) => {
-    await backendSrv.delete(`/api/folders/${uid}`);
+    await backendSrv.delete(`/api/folders/${uid}?forceDeleteRules=true`);
     locationService.push('/dashboards');
   };
 }