Add dialog token auth check on subscriptions

[oskogstad]

Introduction

GraphQL subscriptions currently requires a valid JWT.
However, when subscribing to a topic, there are no checks for auth/validity of the dialogID.
This is a possible attack surface

Implementation

Require a DialogToken when subscribing to a topic.
Check the i claim against the subscription dialogId

Tasks

Beta Give feedback

1. Add check for DialogToken with HTTP request interceptor in hot chocolate
2. Prepare documentation (if relevant - either update working document, or add a new file in docs)
3. Add e2e-test (if relevant)

Threat modelling

Beta Give feedback

1. Does this change introduce any potential security issues?