Allow to update value streams with GraphQL

What does this MR do and why?

Introduce GraphQL mutation to update value streams in GraphQL.

related to #410340 (closed)

How to set up and validate locally

1. Make sure you are on premium tier
2. Get a value stream global id by creating one with these steps or taking an existing one using Rails console with Analytics::CycleAnalytics::ValueStream.last.to_global_id.to_s.
3. Execute the following mutation with graphql-explorer:

mutation updateValueStream {
  valueStreamUpdate(input: { id: VALUE_STREAM_GLOBAL_ID, name: "New Name" }) {
    valueStream {
      id
      name
    }
    errors
  }
}

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.