[App Configuration] - Add query param policy

[zhiyuanliang-ms]

Why this PR?

Adds a new pipeline to update the query params to make sure they are all lowercase and in alphabetical order. This is required for support of Azure Front Door as a CDN.

[Copilot]

Pull Request Overview

This PR adds a new query parameter normalization pipeline policy to the Azure App Configuration SDK. The policy ensures query parameters are lowercase and sorted alphabetically to support Azure Front Door as a CDN.

• Implements a new QueryParamPolicy that transforms query parameters to lowercase and sorts them alphabetically
• Adds comprehensive test coverage for various query parameter scenarios including duplicates and encoded values
• Removes the unused ApiVersionPolicy class as part of cleanup

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
QueryParamPolicy.cs	New pipeline policy that normalizes query parameters by converting to lowercase and sorting alphabetically
QueryParamPolicyTests.cs	Comprehensive test suite covering lowercase conversion, sorting, duplicate handling, and value preservation
ConfigurationClient.cs	Integration of the new QueryParamPolicy into the HTTP pipeline
ApiVersionPolicy.cs	Removal of unused ApiVersionPolicy class
assets.json	Version tag update for the changes

[jimmyca15]

I suggest putting a summary on the class that describes what it is for.