Compatible the HTTP header properties with SNIP-279

[shibd]

Motivation

After snip-279, all properties keys and values use json string save to header: X-Pulsar-Property

This PR to compatible with this change when using subscription admin API.

Also, Using snip-279 also avoids the issue where the Go HTTP client automatically formats HTTP headers: https://github.com/golang/go/issues/37834, This will impact the peek command, the previous method might retrieve properties with inconsistent casing compared to the user-defined.

Modifications

• Compatible the HTTP header properties with SNIP-279

Verifying this change

• Add TestPeekMessageWithProperties to cover this.

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API: (yes / no)
• The schema: (yes / no / don't know)
• The default values of configurations: (yes / no)
• The wire protocol: (yes / no)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / GoDocs / not documented)
• If a feature is not applicable for documentation, explain why?
• If a feature is not documented yet in this PR, please create a followup issue for adding the documentation