[Code health] Handle missing value when image is skipped

[rfontanarosa]

  getFirebaseImageURLs() {
    this.tasks?.forEach(task => {
      if (task.type === this.taskType.PHOTO) {
        const submissionImage = this.getTaskSubmissionResult(task)!
          .value as string;
        const imageRef = ref(this.storage, submissionImage);
        getDownloadURL(imageRef).then(url => {
          this.firebaseURLs.set(submissionImage, url);
        });
      }
    });
  }

submission.service.ts:91 ERROR TypeError: Cannot read properties of undefined (reading 'value')
    at submission-panel.component.ts:75:68
    at List.__iterate (immutable.es.js:3338:11)
    at List.forEach (immutable.es.js:4854:17)
    at SubmissionPanelComponent.getFirebaseImageURLs (submission-panel.component.ts:73:17)
    at Object.next (submission-panel.component.ts:61:16)
    at ConsumerObserver.next (Subscriber.js:113:33)
    at Subscriber._next (Subscriber.js:80:26)
    at Subscriber.next (Subscriber.js:51:18)
    at Subject.js:69:34
    at Object.errorContext (errorContext.js:22:9)

[gino-m]

Instead of throwing an error we should show the "Skipped" text as we do for other values. In the near future we'll make "skipped" explicit, but for now ok to rely on null.

@nwkotto Would you like to take this one?

[nwkotto]

It looks like this has already been fixed. The "Take a photo" section now says "Skipped" and I see a conditional in the code for that case that isn't in what Roberto posted.

There is a separate issue, which is that sometimes there's an image url but I get an "Object ... does not exist" error and the "Take a photo" section just appears blank
. Not sure if this is something the user will actually encounter, though, or it's just a messy test database.