Revert "Merge branch '233447-fix-sourcegraph-not-loading-from-asset-host' into 'master'"

What does this MR do?

This MR reverts !45850 (merged) which attempted to fix a location-specific issue caused by loading Sourcegraph assets from the rails host vs. the asset host. Unfortunately it turned out that the Sourcegraph scripts do not work across origin (see #233447 (comment 435357742)), so this "fix" actually broke the feature for everyone.

By temporarily reverting the "fix", we will at least have the feature working for some people while we contribute a fix upstream.