ci: fix docs publishing for beta tag (#7018)

docs/build.sh

@@ -19,6 +19,7 @@ echo $?
 # Publish only from merge commits and beta release tags
 if [[ -n $CI ]]; then
   if [[ -z $CI_PULL_REQUEST ]]; then
+    eval "$(../ci/channel-info.sh)"
     if [[ -n $CI_TAG ]] && [[ $CI_TAG != $BETA_CHANNEL* ]]; then
       echo "not a beta tag"
       exit 0