refactor(Authoring Tool): Remove old branch authoring route and component

[hirokiterashima]

Changes

• Removed route and component that we used to create and edit branches.

Test

• AT loads and works as before, and the old branch authoring route is no longer accessible.

[hirokiterashima]

:tada: This issue has been resolved in version 5.158.0 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: