Remove echo from gradle plugin

When using this plugin and running e.g. `gradle --quiet`, the echo statement would print to stdout. I figured that I could make it respect the `--quiet` flag (and possibly various other situations in which echoing isn't expected to print to stdout), but as a much simpler approach it can also be removed altogether unless there is a reason to keep it.

plugins/gradle/gradle.plugin.zsh

@@ -15,7 +15,6 @@ function gradle-or-gradlew() {
 
   # if gradlew found, run it instead of gradle
   if [[ -f "$project_root/gradlew" ]]; then
-    echo "executing gradlew instead of gradle"
     "$project_root/gradlew" "$@"
   else
     command gradle "$@"