Expand Goss tests for Connect

[!NOTE]
Moved from rstudio/platform-team#413

Context

Connect images have goss tests but coverage could be expanded, particularly for content execution and runtime integration.

Current goss test templates

• https://github.com/posit-dev/images-connect/blob/main/connect/template/test/goss.yaml.jinja2 (153 lines)
• https://github.com/posit-dev/images-connect/blob/main/connect-content/template/test/goss.yaml.jinja2
• https://github.com/posit-dev/images-connect/blob/main/connect-content-init/template/test/goss.yaml.jinja2

Current coverage

Tests check: users, groups, packages, ports, processes, files, and commands.

Potential expansion areas

• Connect API health endpoint verification
• R, Python, and Quarto runtime availability within the container
• Content execution smoke tests (deploy and run basic content)
• ODBC driver installation and configuration
• Connect startup and configuration loading
• License activation and status
• Content-init sidecar container readiness and transfer verification

Related: #458 (centralize common goss patterns)

Start with the three current goss test templates linked in the issue and review related issue #458 for shared patterns. Compare the existing checks with the proposed areas, then clarify which coverage is in scope; done should be an agreed set of expanded tests covering the selected Connect runtime, startup, integration, or sidecar behavior.