feat: configure Playwright service to allow running in headed mode

make environment variables available so that the DISPLAY variable can
be specified for the host platform, and mount the XServer Unix
socket.

Author: angela-tran

compose.yml

@@ -46,7 +46,9 @@ services:
     build:
       context: .
       dockerfile: tests/playwright/Dockerfile
+    env_file: .env
     image: benefits_client:playwright
     volumes:
       - ./tests/playwright:/playwright
+      - /tmp/.X11-unix:/tmp/.X11-unix
     command: ./run.sh