Gatsby: Remove broken avatar image on gatsbygram example

[m-allanson]

Description

The post detail page on https://gatsbygram.gatsbyjs.org is missing the avatar image. This should be updated to fix the image, or if that's not possible, remove the image completely.

Getting started

The Gatsbygram code can be found in the example directory of this repo.

The avatar is rendered in post-detail.js and the browser tests are in home-page-spec.js. Run the browser tests (built with cypress.io) with yarn run cy:run.

For reference there's a recent PR that fixes this for the gatsbygram homepage.

Steps to reproduce

• Visit https://gatsbygram.gatsbyjs.org
• Click on one of the posts
• See question mark next to the username

Expected result

Either the correct image, or if that's not possible then remove the image.

Actual result

It's trying to show an image that's not available.

Environment

n/a

[DylanTackoor]

I'll take a stab at fixing this today 😄

[FrederikBolding]

As it didn't seem to have been looked at yet, and I was mocking about with example anyway, I fixed it in #12371