skip over broken keys instead of aborting

Errors will show up in the logs in this case with detailed information
about what broke.

In the future we should add some kind of database integrity check
functionality and also functionality to repair/delete broken data, but
for now this at least makes it work 99.99% of the time.

src/service/admin.rs

@@ -844,7 +844,10 @@ impl Service {
                 });
 
                 while let Some(mxc) = rx.recv().await {
-                    let mxc = mxc?;
+                    let Ok(mxc) = mxc else {
+                        continue;
+                    };
+
                     let server_name = mxc.server_name();
 
                     if server_name == Ok(services().globals.server_name()) {