fix: improve Docker build process

- Fix ngrok authtoken configuration

- Improve layer caching

- Add better error handling

(cherry picked from commit deb8b2a96569f238cfe696bcbedfcd1de2fdc3f7)

Author: danfmaia

Dockerfile

@@ -16,7 +16,7 @@ RUN apt-get update && \
 
 # Set up ngrok authtoken (using the v3.x command)
 ARG NGROK_AUTHTOKEN
-RUN ngrok config add-authtoken $NGROK_AUTHTOKEN
+RUN ngrok config add-authtoken "${NGROK_AUTHTOKEN}"
 
 # Install virtualenv to manage Python dependencies inside the container
 RUN pip install virtualenv