.NET SDK auto PR not created if generation succeeded but build failed

When .NET SDK generation succeeds but the build fails, we should still create the auto PR.
Because service team have breaking changes from time to time, it will cause `dotnet build` failure for sure. And it would need manual fix to mitigate the breaking changes, and we need the PR to proceed.

Start by locating the .NET SDK generation and auto-PR workflow in this tools repository, then trace what happens after generation succeeds and `dotnet build` fails. Confirm the current behavior and identify where the workflow decides whether to create the PR; done means a PR is still created so generated changes can receive manual fixes.

Written by the indexing model from the issue text.