Microsoft.Build.Locator dependency is not source-buildable

Because the sdk includes the dotnet-format tool in .NET 6.0, dotnet-format needs to be included in source-build. This means all the source dependencies must also be source-built. The `Microsoft.Build.Locator` dependency is not included in .NET 6.0 source-build and is not something that would be very easy to support because it doesn't utilize arcade and because of its VS dependencies. Given source-build doesn't support Windows, is there a way to remove this dependency ((https://github.com/dotnet/format/blob/main/src/Commands/FormatCommandCommon.cs#L344) for source-built versions of dotnet-format?