[CI] Enable CI binary build for the vertical federated learning branc…

…h. (#10417)

Co-authored-by: Philip Hyunsu Cho <[email protected]>

tests/buildkite/conftest.sh

@@ -47,7 +47,7 @@ else
 fi
 export BRANCH_NAME=${BRANCH_NAME//\//-}
 
-if [[ $BRANCH_NAME == "master" || $BRANCH_NAME == "release_"* ]]
+if [[ $BRANCH_NAME == "master" || $BRANCH_NAME == "release_"* || $BRANCH_NAME == "vertical-federated-learning" ]]
 then
   is_release_branch=1
   enforce_daily_budget=0