Include "EnableProxyProtocol" parameter to private-link-service create and update

[sumeetmittal]

Resource Provider
What is the Azure resource provider your feature is part of?
Network Resource Provider

Description of Feature or Work Requested
Provide a brief description of the feature or work requested. A link to conceptual documentation may be helpful too.
Include "EnableProxyProtocol" parameter to private-link-service create and update
https://docs.microsoft.com/en-us/cli/azure/network/private-link-service?view=azure-cli-latest#az-network-private-link-service-create
https://docs.microsoft.com/en-us/cli/azure/network/private-link-service?view=azure-cli-latest#az-network-private-link-service-update

Minimum API Version Required
What is the minimum API version of your service required to implement your feature?
Latest

Swagger Link
Provide a link to the location of your feature(s) in the REST API specs repo. If your feature(s) has corresponding commit or pull request in the REST API specs repo, provide them. This should be on the master branch of the REST API specs repo.
https://docs.microsoft.com/en-us/rest/api/virtualnetwork/privatelinkservices/createorupdate
Also reach out to Bo Wen for any more information

Target Date
If you have a target date for release of this feature/work, please provide it. While we can't guarantee these dates, it will help us prioritize your request against other requests.
2/14 is GA date. this needs to be included and published before 2/14.

[arrownj]

Hi @myronfanqiu , could you please help take a look at this ?

[mmyyrroonn]

@sumeetmittal Hello. This has been down in this PR. #12021 thanks.