fix(docker): enable track_functions in postgres config

Add track_functions=all to postgres command to support function
statistics tracking required by test_helpers_test.

This was previously configured in Dockerfile.pgtap but needed
for standard postgres images.

Author: tobyhede

tests/docker-compose.yml

@@ -2,6 +2,7 @@ services:
   postgres: &postgres
     container_name: postgres
     image: postgres:17
+    command: postgres -c track_functions=all
     ports:
       - 7432:7432
     environment: