fix(docker): add NLP_CONF_FILE to runtime environment in docker-compose-transformers.yml

[sriram687]

Summary

docker-compose-transformers.yml passes NLP_CONF_FILE only as a Docker
build-time ARG but omits it from the container's runtime environment: block.

Since app.py reads this value via os.environ.get("NLP_CONF_FILE") at
startup, the build ARG alone is not sufficient to guarantee the correct
NLP engine config is loaded at runtime.

Change

     environment:
       - PORT=5001
+      - NLP_CONF_FILE=presidio_analyzer/conf/transformers.yaml

Why this matters

• app.py reads NLP_CONF_FILE via os.environ.get() at runtime
• Without this, the env var is absent in override/direct-run scenarios
• Makes config explicit, overridable, without rebuilding the image

Fixes

Fixes #2048