Fix prebuild scripts one more time (#55059)

* Better

* Update build.sh

I made it a little bit shorter. 
The main value here that you changed negative condition with positive one. That excludes the cases when some error occur in condition. Since some error during calculation a predicate does not mean that predicate is false logically. It means predicate is just failed. Bash is hard in distinguishing such cases.

* Update build.sh

---------

Co-authored-by: Sema Checherinda <104093494+CheSema@users.noreply.github.com>

docker/packager/binary/build.sh

@@ -55,15 +55,21 @@ ccache_status
 # clear cache stats
 ccache --zero-stats ||:
 
+function check_prebuild_exists() {
+  local path="$1"
+  [ -d "$path" ] && [ "$(ls -A "$path")" ]
+}
+
 # Check whether the directory with pre-build scripts exists and not empty.
-if [ ! -d "/build/packages/pre-build" ] || [ -n "$(ls -A /build/packages/pre-build)" ]; then
-   echo "There are no subcommands to execute :)"
-else
+if check_prebuild_exists /build/packages/pre-build
+then
   # Execute all commands
   for file in /build/packages/pre-build/*.sh ;
   do
     bash "$file"
   done
+else
+  echo "There are no subcommands to execute :)"
 fi
 
 if [ "$BUILD_MUSL_KEEPER" == "1" ]