Close events SSE connection when notebook complete

When the execution is complete and the HTML is available (html_hash is
set) we can stop watching the /events endpoint because nothing is going
to change.

Also clean up logging. Only make console.error statements on errors; we
no longer need regular logging of all actions.

apps/squareone/src/components/TimesSquareHtmlEventsProvider/TimesSquareHtmlEventsProvider.js

@@ -32,7 +32,7 @@ export default function TimesSquareHtmlEventsProvider({ children }) {
           signal: abortController.signal,
           onopen(res) {
             if (res.status >= 400 && res.status < 500 && res.status !== 429) {
-              console.log(`Client side error ${fullHtmlEventsUrl}`, res);
+              console.error(`Client side error ${fullHtmlEventsUrl}`, res);
             }
           },
           onmessage(event) {
@@ -43,9 +43,21 @@ export default function TimesSquareHtmlEventsProvider({ children }) {
               return;
             }
             setHtmlEvent(parsedData);
+
+            if (
+              parsedData.execution_status == 'complete' &&
+              parsedData.html_hash
+            ) {
+              abortController.abort();
+            }
           },
           onclose() {},
-          onerror(err) {},
+          onerror(err) {
+            console.error(
+              `Error fetching Times Square events SSE ${fullHtmlEventsUrl}`,
+              err
+            );
+          },
         });
       }
     }