[OpenAPI] Improve missing query parameter error

[tobias-tengler]

No description provided.

[Copilot]

Pull request overview

This PR aims to improve the HTTP endpoint error returned when a required query parameter is missing, providing a clearer 400 Bad Request response and adding a regression test for the behavior.

Changes:

• Add a new GET integration test covering missing required query parameters and snapshot the expected problem+json response.
• Extend the test schema with a paginated search field requiring a non-null argument.
• Update DynamicEndpointMiddleware to throw a BadRequestException when a required route/query parameter is missing.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/HotChocolate/Adapters/test/Adapters.OpenApi.Tests/TestSchema.cs	Adds SearchProductsPaginated to support the new integration test scenario.
src/HotChocolate/Adapters/test/Adapters.OpenApi.Tests/Endpoints/HttpEndpointIntegrationTestBase.cs	Adds an integration test for a missing required query parameter.
src/HotChocolate/Adapters/test/Adapters.OpenApi.Tests/Endpoints/snapshots/HttpEndpointIntegrationTestBase.Http_Get_With_Missing_Required_Query_Parameter.snap	Adds the expected 400 problem+json snapshot output.
src/HotChocolate/Adapters/src/Adapters.OpenApi.Core/Execution/DynamicEndpointMiddleware.cs	Adds missing-required parameter checks for route/query parameters.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.00%. Comparing base (d731a0c) to head (8da578a).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@     Coverage Diff      @@
##   main   #9492   +/-   ##
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