keep going when one deletion fails in delete-remote-media

We *should* ensure that media deletion is always successful, but when a
bug causes a single object to fail deletion it's better to try to delete
the remaining objects than to give up entirely.

src/service/admin.rs

@@ -807,6 +807,7 @@ impl Service {
                 });
 
                 let mut failed_keys = 0;
+                let mut failed_deletes = 0;
                 while let Some(mxc) = rx.recv().await {
                     let Ok(mxc) = mxc else {
                         // Error details are logged by media::iter_all
@@ -825,10 +826,18 @@ impl Service {
                         }
                     }
 
-                    count += 1;
+                    // Technically this can be collapsed, but relying on &&
+                    // short-circuiting to avoid the delete side-effect is
+                    // confusing.
+                    #[allow(clippy::collapsible_if)]
                     if !dry_run {
-                        services().media.delete(mxc).await?;
+                        if services().media.delete(mxc).await.is_err() {
+                            // Error details are logged by media::delete
+                            failed_deletes += 1;
+                            continue;
+                        }
                     }
+                    count += 1;
                 }
 
                 let mut message = if dry_run {
@@ -844,6 +853,17 @@ impl Service {
                          database."
                     )
                     .unwrap();
+                }
+
+                if failed_deletes != 0 {
+                    write!(
+                        message,
+                        "\n{failed_deletes} media objects failed to delete."
+                    )
+                    .unwrap();
+                }
+
+                if failed_keys != 0 || failed_deletes != 0 {
                     write!(
                         message,
                         "\nCheck the server logs for more details."