Download smaller images on the watch

[mchowning]

Description

Instead of downloading 960 pixel images like we do on the phone, let's just download 480 pixel images on the watch. This will reduce the watch's data usage and improve the initial login and sync time. Thanks for the suggestion @geekygecko . 🙇

Testing Instructions

1. Log into a fresh install of the app
2. Use the network inspector to verify that 480 pixel images are being instead of 960 pixel images
3. Check the UI in the app to make sure the images still look good. I believe the larges image we display in the watch app is the podcast artwork we display at the top of the screen for a particular podcast.

Screenshots or Screencast

Checklist

• If this is a user-facing change, I have added an entry in CHANGELOG.md
• I have considered whether it makes sense to add tests for my changes

[ashiagr]

Good call 👍