fix transcoding query overwrites body/route parameters

[DeagleGross]

Fixed issue where in query parameter processing overwrites route or body-bound fields.

[Copilot]

Pull request overview

Fixes JSON transcoding request binding precedence so query string parameters cannot overwrite values already bound from route parameters or the HTTP body (including when query keys use JSON-name aliases).

Changes:

• Prevent query binding for body-bound fields using both proto field names and JSON names (including nested prefixes).
• Prevent query binding for route-bound fields when query keys match the route field’s JSON path alias.
• Add/extend tests and update the test proto to cover JSON-name alias scenarios.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/Grpc/JsonTranscoding/src/Microsoft.AspNetCore.Grpc.JsonTranscoding/Internal/JsonRequestHelpers.cs	Extends query-binding filter to block overwrites of body/route-bound fields via proto and JSON names.
src/Grpc/JsonTranscoding/src/Microsoft.AspNetCore.Grpc.JsonTranscoding/Internal/CallHandlers/CallHandlerDescriptorInfo.cs	Precomputes a set of route parameter JSON paths for fast alias checks during query binding.
src/Grpc/JsonTranscoding/test/Microsoft.AspNetCore.Grpc.JsonTranscoding.Tests/UnaryServerCallHandlerTests.cs	Adds regression tests ensuring query params (proto/JSON aliases) don’t overwrite route/body values.
src/Grpc/JsonTranscoding/test/Microsoft.AspNetCore.Grpc.JsonTranscoding.Tests/Proto/transcoding.proto	Adds sub_data to exercise JSON-name prefix behavior for body-bound fields.