Better fallback handling for popover modal image loading

[rossgalloway]

What type of issue is this?

Minor Change

What needs to be shipped?

The Navigation popover modal loads images from the CDN, and if there is an issue with those images or the CDN then this makes the whole site wait on resolution to load.

• We need to load things without relying on images loading. Generally this seems the case. Maybe only an issue with the YearnApps.tsx file?
• Add a function that wraps the CDN URL with inputs for chainId and address and processes them to assure they are valid and address is lowercased.