fix(proto): protobuf exports may be incorrect if minimized

[mjameswh]

What changed

• In a few places, we reflectively visit and transform our protobuf definitions. To determine the type of node being visited (Root, Namespace or Type), we would previously check the object's constructor.name. However, that name could get mangled if the package was bundled and minimized, which would generally result in error messages such as:

  <app-dir>/node_modules/@temporalio/client/src/types.ts:62
  export const { WorkflowService } = proto.temporal.api.workflowservice.v1;
                                                    ^
  TypeError: Cannot read properties of undefined (reading 'api')
  

  We now check constructor.className instead, which is a convenient property added by the protobufjs library, specifically for the purpose of reflection.

Note

• We provide no guarantee regarding the inclusion of @temporalio/* packages as part of bundled and/or minimized applications. We do not test such usage at this time. We strongly recommend configuring your bundler to treat these packages as external.

[bergundy]

Let's always use className but otherwise LGTM.
Thanks!

[iamnafets]

Wow this bug driving me absolutely crazy, thanks for the PR.

Adding a next.js PR to make this package external by default:
vercel/next.js#58573