fix: decouple mongoDB integration tests (#16306)
fix: decouple mongoDB integration tests (#16306)

The container requests where using same fixed, exposed port, instead of
using the random one. In this commit we are calculating the exposed port
in the getContainer method, returning the endpoint for the container
in order to be used by each test
open-telemetry/opentelemetry-collector-contrib,open-telemetry/opentelemetry-collector-contrib