This also removes the WorkflowClientOptions.workflowDefaults.

Reasoning:

• Workflow IDs should represent a meaningful business ID
• Workflow IDs can be used as an idempotency key when starting workflows from an external signal
• workflowDefaults were removed because their presence made taskQueue optional in WorkflowOptions, omitting it from both the defaults and options resulted in runtime errors where we could have caught those at compile time.\

Migration:

// Before
const client = new WorkflowClient(conn.service, { workflowDefaults: { taskQueue: 'example' } });
const handle = await client.start(myWorkflow, { args: [foo, bar] });
// After
const client = new WorkflowClient(conn.service);
const handle = await client.start(myWorkflow, {
  args: [foo, bar],
  taskQueue: 'example',
  workflowId: 'a-meaningful-business-id',
});