Missing `webp` in Webpack configs for image file loader

[adamstankiewicz]

frontend-build/config/webpack.prod.config.js

Line 149 in 5b32f9d

test: /\.(jpe?g|png|gif)(\?v=\d+\.\d+\.\d+)?$/,

Ensure ALL webpack configs (not just the above production config) properly handles loading webp file extensions.

(more deets to come)