Bug 1944432 - Set background update reasons to not update correctly. r=chutten,application-update-reviewers,bytesized

First, this commit awaits the helper method.

Second, this commit removes `testGetValue`, which should never have
been used in production code -- it is test-only.  Overflow errors will
be caught and recorded by Glean.

Differential Revision: https://phabricator.services.mozilla.com/D229567

Author: ncalexan

toolkit/mozapps/update/BackgroundUpdate.sys.mjs

@@ -281,7 +281,7 @@ export var BackgroundUpdate = {
       reasons.push(this.REASON.MANUAL_UPDATE_ONLY);
     }
 
-    this._recordGleanMetrics(reasons);
+    await this._recordGleanMetrics(reasons);
 
     return reasons;
   },
@@ -337,7 +337,7 @@ export var BackgroundUpdate = {
       }
     }
 
-    this._recordGleanMetrics(reasons);
+    await this._recordGleanMetrics(reasons);
 
     return reasons;
   },
@@ -991,28 +991,15 @@ export var BackgroundUpdate = {
   /**
    * Local helper function to record all reasons why the background updater is
    * not used with Glean. This function will only track the first 20 reasons.
-   * It is also fault tolerant and will only display debug messages if the
-   * metric cannot be recorded for any reason.
    *
-   * @param {array of strings} [reasons]
+   * @param {[string]} [reasons]
    *        a list of BackgroundUpdate.REASON values (=> string)
    */
   async _recordGleanMetrics(reasons) {
     // Record Glean metrics with all the reasons why the update was impossible.
     for (const [key, value] of Object.entries(this.REASON)) {
       if (reasons.includes(value)) {
-        try {
-          // `testGetValue` throws a `DataError` in case
-          // of `InvalidOverflow` and other outstanding errors.
-          Glean.backgroundUpdate.reasonsToNotUpdate.testGetValue();
-          Glean.backgroundUpdate.reasonsToNotUpdate.add(key);
-        } catch (e) {
-          // Debug print an error message and break the loop to avoid Glean
-          // messages on the console would otherwise be caused by the add().
-          lazy.log.debug("Error recording reasonsToNotUpdate");
-          console.log("Error recording reasonsToNotUpdate");
-          break;
-        }
+        Glean.backgroundUpdate.reasonsToNotUpdate.add(key);
       }
     }
   },