fix: unify default latency test URL and update workflows/backend logic

- All delay test logic, Rust MihomoManager, API, cmds, delay.ts, settings, and group editor now use the Cloudflare 204 test URL
- Fixed outdated URLs in docs and comments
- Fix Github Actions workflow: unexpected neeeds run

src/components/profile/groups-editor-viewer.tsx

@@ -454,7 +454,7 @@ export const GroupsEditorViewer = (props: Props) => {
                       <ListItemText primary={t("Health Check Url")} />
                       <TextField
                         autoComplete="new-password"
-                        placeholder="https://www.gstatic.com/generate_204"
+                        placeholder="https://cp.cloudflare.com/generate_204"
                         size="small"
                         sx={{ width: "calc(100% - 150px)" }}
                         {...field}