[Blazor] Consider passing argsJson as byte[] from the client to dispatcher calls

[pranavkm]

We could avoid doing work on the server to convert UTF16 string -> UTF8 byte array and instead have the client pass in the correctly encoded byte array. There's an API and polyfill to produce a utf8 byte array in the browser - https://github.com/samthor/fast-text-encoding

[pranavkm]

Since this isn't user visible, it should be safe to do this as part of a future milestone.