[clang-format] Microsoft style fixes for C# properties

Summary:
There should be no line break before the opening brace for Microsoft style property accessors when the accessor is a simple `{ get; set }`.

https://docs.microsoft.com/en-us/dotnet/csharp/properties

Reviewers: krasimir, MyDeveloperDay

Reviewed By: krasimir

Subscribers: cfe-commits

Tags: #clang-format, #clang

Differential Revision: https://reviews.llvm.org/D81467