Update to use new Process APIs in .NET 11

Lots of places in this repo use the `Process` API to orchestrate launching of processes and reading of their output. This is especially true for the tools like `dotnet-user-secrets`, `dotnet-user-jwts`, and `dotnet-watch`. It's also very likely in tests.

We should consider updating these places to use the [new process APIs introduced in .NET 11](https://devblogs.microsoft.com/dotnet/process-api-improvements-in-dotnet-11/).