Add diagnostic log to catch events without an ID

This adds some temporary logging to investigate
element-hq/element-web#11120.

src/components/views/rooms/EventTile.js

@@ -495,6 +495,12 @@ module.exports = createReactClass({
             return null;
         }
         const eventId = this.props.mxEvent.getId();
+        if (!eventId) {
+            // XXX: Temporary diagnostic logging for https://github.com/vector-im/riot-web/issues/11120
+            console.error("EventTile attempted to get relations for an event without an ID");
+            // Use event's special `toJSON` method to log key data.
+            console.log(JSON.stringify(this.props.mxEvent, null, 4));
+        }
         return this.props.getRelationsForEvent(eventId, "m.annotation", "m.reaction");
     },