fix: set gitlab-shell.service.internalPort to number

What does this MR do?

Sets the GitLab Charts value gitlab-shell.service.internalPort as an integer rather than a string.

If set to a string, the gitlab_charts : Install GitLab Charts ansible task will fail:

Failure log

TASK [gitlab_charts : Install GitLab Charts] ***********************************
fatal: [localhost]: FAILED! => changed=false 
  command: /usr/bin/helm --version=7.9.2 upgrade -i --reset-values -f=/tmp/tmpag8l7byd.yml gitlab gitlab/gitlab
 failed_when_result: true
  msg: |-
    Failure when executing Helm command. Exited 1.
    stdout:
    stderr: Error: UPGRADE FAILED: values don't meet the specifications of the schema(s) in the following chart(s):
    gitlab-shell:
    - service.internalPort: Invalid type. Expected: number, given: string
  stderr: |-
    Error: UPGRADE FAILED: values don't meet the specifications of the schema(s) in the following chart(s):
    gitlab-shell:
    - service.internalPort: Invalid type. Expected: number, given: string
  stderr_lines: <omitted>
  stdout: ''
  stdout_lines: <omitted>

Confirmed gitlab-shell chart expected value is number:

values.schema.json snippet

``` "service": { "internalPort": { "title": "Service internal port", "type": "number" }, } ```

Tested in a sandbox environment by overriding the value set by GET, results were successful ✅. Details in this thread.

Related issues

Related internal issues:

• https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/team/-/issues/4742
• https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/instrumentor/-/merge_requests/3163

Author's checklist

When ready for review, the Author applies the workflowready for review label and mention @gl-quality/get-maintainers:

• Merge request:
  • Corresponding Issue raised and reviewed by the GET maintainers team.
  • Merge Request Title and Description are up-to-date, accurate, and descriptive
  • MR targeting the appropriate branch
  • MR has a green pipeline
  • MR has no new security alerts in the widget from the Secret Detection and IaC Scan (SAST) jobs.
• Code:
  • Check the area changed works as expected. Consider testing it in different environment sizes (1k,3k,10k,etc.).
  • Documentation created/updated in the same MR.
  • If this MR adds an optional configuration - check that all permutations continue to work.
  • For Terraform changes: set up a previous version environment, then run a terraform plan with your new changes and ensure nothing will be destroyed. If anything will be destroyed and this can't be avoided please add a comment to the current MR.
• Create any follow-up issue(s) to support the new feature across other supported cloud providers or advanced configurations. Create 1 issue for each provider/configuration. Contact the Quality Enablement team if unsure.