tus: sentry improvements

## Ticket
910

## Changes
- Change the "message" from a generic "tus-upload" to more specific ones like "tus: failed to resume upload". These are grouped as "Events" in sentry, so we can isolate and search for them easily.

- Pass more info to Sentry (previously only available from Slack). It is still good to send to both, since some browsers block Sentry even without blocker extensions.

- Reduce verbosity of Slack's

## Notes
- Was unable to change the "unknown" problem mentioned in the ticket. The API does not accept `new Error('xxx')`, even though that's being mentioned by many in the forums. It might be due to the version of Sentry that we are using.

- To search for tus issues, go to "Issues" and query `message:tus*`. Results are collapsed per event, so click on the item of interest, then click "Events" at the upper right to see all occurrences of the same problem.

web/setup/publish-v2.js

@@ -24,6 +24,15 @@ function inStatusCategory(status, category) {
   return status >= category && status < category + 100;
 }
 
+function getTusErrorType(errMsg: string) {
+  if (errMsg.startsWith('tus: failed to upload chunk at offset')) {
+    // This is the only message that contains dynamic value prior to the first comma.
+    return 'tus: failed to upload chunk at offset';
+  } else {
+    return errMsg.startsWith('tus:') ? errMsg.substring(0, errMsg.indexOf(',')) : errMsg;
+  }
+}
+
 export function makeResumableUploadRequest(
   token: string,
   params: FileUploadSdkParams,
@@ -86,14 +95,12 @@ export function makeResumableUploadRequest(
         }
 
         window.store.dispatch(doUpdateUploadProgress({ guid, status: 'error' }));
-        analytics.sentryError('tus-upload', err);
+        analytics.sentryError(getTusErrorType(errMsg), { onError: err, tusUpload: uploader });
 
         reject(
           // $FlowFixMe - flow's constructor for Error is incorrect.
           new Error(customErr || err, {
             cause: {
-              url: uploader.url,
-              status,
               ...(uploader._fingerprint ? { fingerprint: uploader._fingerprint } : {}),
               ...(uploader._retryAttempt ? { retryAttempt: uploader._retryAttempt } : {}),
               ...(uploader._offsetBeforeRetry ? { offsetBeforeRetry: uploader._offsetBeforeRetry } : {}),