web: remove `.theme-redesign` usage from shared
Created by: 5h1rU
Changes
- Removed
.theme-redesign
usage from branded.
Part of https://github.com/sourcegraph/sourcegraph/issues/20847.
Created by: 5h1rU
.theme-redesign
usage from branded.Part of https://github.com/sourcegraph/sourcegraph/issues/20847.