Allow optional cacheID on the persisted-id RequestParameters variant

[GregoryCollett]

Summary

When the relay-compiler is configured with include_query_text: true for persisted queries, generated artifacts carry a persisted id, the query text, and a cacheID (a hash of the text, used for local caching) all at once.

The current RequestParameters union only permits cacheID on the text-only variant (the one with id: null):

export type RequestParameters =
  | {
      readonly id: string,
      readonly text: string | null,
      // ...no cacheID
    }
  | {
      readonly cacheID: string,
      readonly id: null,
      readonly text: string | null,
      // ...
    };

So an artifact with a non-null id plus a cacheID does not type-check against either variant. This PR adds an optional readonly cacheID?: string to the persisted-id variant, which makes that compiler configuration representable without altering the existing text-only variant.

This is a purely additive, optional field — no runtime behaviour changes, and existing artifacts that omit cacheID are unaffected.

Motivation

We run relay-compiler with persistConfig + include_query_text: true so that artifacts carry both a persisted id (for id-first / trusted-documents requests) and the text (for a safe deploy transition), together with the cacheID the compiler emits for local caching. The type currently doesn't describe artifacts that have all three, which we've been carrying as a local patch.

Test plan

Type-only change to a Flow definition; adding an optional field to one member of the union is backwards compatible. RequestParameters continues to type-check for all existing shapes, and now also accepts { id, text, cacheID }.

[captbaritone]

Thanks! This matches the Flow types. Makes sense.

[meta-codesync]

@captbaritone has imported this pull request. If you are a Meta employee, you can view this in D114794036.