scripts: remove unittest.mock dependency when not used

Found upon inspection.

Signed-off-by: Andres Gomez <agomez@igalia.com
Reviewed-and-Tested-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4840>
1 file changed