misc/broot: Unbreak build with CLIENT_SERVER

client-server is no longer feature gated, so
we can safely remove the OPTION all together.

> Building for broot-1.6.1_1

error: Package broot v1.6.1 does not have the feature client-server`

Reported-by: pkg-fallout
(cherry picked from commit 12d04cda7dd3f8d299acf0dce323bc665014f698)