grpc instrumentation requires @grpc/grpc-js types but doesn't depend on it

[Flarna]

This results in build failures if consumer has @grpc/grpc-js not installed for other reasons.

Refs: open-telemetry/opentelemetry-js-contrib#1358 (comment)

[pichlermarc]

Thinking that #3386 could be causing this issue, as it uses the types from grpc and grpc-js in the instrumentation's public API.
I am doing some tests locally to verify.

Edit: looks like it is not actually using it in its public API, continuing to investigate.

[Flarna]

Took a look into the generated .d.ts files:

• index.d.ts imports ./types
• types.d.ts type imports @grpc/grpc-js and grpc

As a result any consumer requires @grpc/grpc-js and @types/grpc.

moving metadataCaptureType away into internal-types.ts as described here should solve this.

[Flarna]

I can create a PR as I have the changes already done local.

[pichlermarc]

Took a look into the generated .d.ts files:

* `index.d.ts` imports  `./types`

* `types.d.ts` type imports `@grpc/grpc-js` and `grpc`

As a result any consumer requires @grpc/grpc-js and @types/grpc.

moving metadataCaptureType away into internal-types.ts as described here should solve this.

Ah, right. Just came to the same conclusion, you beat me to it. Thanks for taking a look.

I can create a PR as I have the changes already done local.

Please do, I'll give it a review right away. 🙂