Add acceptance stage and resolve trusted-merge-branch-verification pipeline job failure

The main WDMS Worker pipeline fails at the moment due to the acceptance stage not being defined. The "acceptance" stage was introduced to the azure pipeline in MR Defining Java Acceptance Test Stage (!1139) · Merge requests · OSDU Software / OSDU Data Platform / CI-CD Pipelines · GitLab.

This MR adds the "acceptance" stage to the list of stages in the .gitlab-ci.yml file. Also this MR addresses previous pipeline failures on the trusted-merge-branch-verification job.