fix: exclude master DB from active geo rep recommendation

[jdmsoss]

Overview/Summary

Master database should be excluded from "Use Active Geo Replication to Create a Readable Secondary in Another Region" recommendation result.

Before my fix 👇

After my fix 👇

As part of this pull request I have

• Read the Contribution Guide and ensured this PR is compliant with the guide
• Checked for duplicate Pull Requests
• Associated it with relevant GitHub Issues or ADO Work Items (Internal Only)
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Ensured PR tests are passing
• Performed testing and provided evidence (e.g. screenshot of output) for any changes associated to ARG queries
• Updated relevant and associated documentation (e.g. Contribution Guide, Docs etc.)