API docs logo missing

[sarayourfriend]

Description

The Openverse API documentation logo is missing: https://api-staging.openverse.org/v1/

To fix this, move the logo into the Openverse API static files and reference it directly served from the API rather than from GitHub user content.

Reproduction

1. Visit https://api-staging.openverse.org/v1/ and see that the logo is missing from the side bar

Additional context

This was caused by #4073 because the API documentation references https://raw.githubusercontent.com/WordPress/openverse/HEAD/brand/logo.svg for the logo specifically (rather than pulling it from the Openverse API's static files, for example).

Marked low priority because while it is ugly, it doesn't cause any problems such that it should be fixed before anything else.