Change Namespace data map to contain bytes

[tdeebswihart]

What changed?
The namespace data map now has bytes values rather than string.

Why?

We embed binary data (cast to strings) here in a few places, and that can cause google/protobuf to yell at us for having string data that's invalid UTF-8. Protobuf strings and bytes are wire-compatible

Breaking changes

This will change all code generated by protoc plugins to use the language's type for raw bytes. I have paired Go API and server PRs that will go along with this change

[cretz]

Not the biggest fan of breaking API compat even for these rarely used APIs, but I understand the reasoning.

You'll have to disable the buf compat detector.

[yycptt]

we are ok with the breaking change for customer when they upgrade sdk?

[yycptt]

Is there a reason we are just fixing this specific field? I think the same thing could happen to, for example, the memo field.

[tdeebswihart]

We've decided to axe this and migrate the relevant fields internally