types: remove dependency on extsvc clients
Created by: bobheadxi
Another way to resolve the import cycle in https://github.com/sourcegraph/sourcegraph/pull/28117 , instead of the reverted https://github.com/sourcegraph/sourcegraph/pull/28149.
The import cycle is caused by types
importing various extsvc
packages that each have clients to their respective external services, causing an import of httpcli
. However, these types are only used in testing - this moves those test types out into types/typestest
(mirroring standard library conventions like http/httptest
). Diff only affects tests.