feat: expose proxy protocol option in API response & CLI

[dhruvjain99]

Proposed Changes

Exposes proxy protocol flag in the listener show cmd & http api.

Types of Changes

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• Bugfix (non-breaking change which fixes issue #XXXX)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
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[ajatprabha]

LGTM