docs: Update blocked ports list for NGINXaaS Azure listen directive

[rnandwal-f5]

Proposed changes

Problem: The NGINX listen port restrictions section in the NGINXaaS for Azure documentation was missing some recent changes for blocked ports. It only mentioned "certain ports" without providing a comprehensive list of all blocked ports, making it difficult for users to understand exactly which ports they cannot use with the listen directive.

Solution: Updated the documentation to include a complete and detailed list of all blocked ports with explanatory descriptions. The changes include:

Added explicit enumeration of all currently blocked ports (19, 21, 70, 119, 49151, 49153, 5140, 50000, 54141, 54779)
Categorized ports by their purpose (Azure health probe restricted ports, Azure system reserved port, internal service ports)
Provided clear explanations for why each port or group of ports is blocked
Maintained the existing bullet point structure for consistency with the rest of the document
This ensures users have complete visibility into port restrictions and understand the technical reasons behind each limitation.

Testing: Verified that the documentation renders correctly in Markdown and that all port numbers and descriptions are accurate. Cross-referenced the port list with current NGINXaaS for Azure restrictions to ensure completeness.

Please focus on: Review the accuracy of the port descriptions and categorizations to ensure they align with the current NGINXaaS for Azure implementation. Confirm that the technical explanations are clear and helpful for users who encounter port conflict

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Footnotes

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[rnandwal-f5]

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