Add details and action items to Azure pre-reqs

[chomipi88]

Affected Document: https://docs.astronomer.io/astro/install-azure#prerequisites

Problem Type (Priority):

• [ ] Error (Critical): This document has existing information that's incorrect and prevents readers from completing the documented setup (Add the error/critical label to this issue)
• [x] Misleading (Important): This document could benefit from additional context, guidance, or clarity (Add the error/FYI label to this issue)
• [ ] Typo (Low): Any issue related to spelling/ punctuation/ formatting (Add the error/typo label to this issue)

Suggested Change (include links to relevant existing docs, support tickets, messages, or external content):

1. Clean up the section about VM SKU and Zonal requirements for Workers
2. Add details about Azure Postgres Flexible Server SKU and Zonal requirements
3. Add action item for end user to raise a support ticket to raise / enable any restrictions found

Additional Notes: