fix: Use Connection class for test env connection property (#1123)

Author: bergundy

packages/testing/src/index.ts

@@ -17,7 +17,6 @@ import {
   AsyncCompletionClient,
   Client,
   ClientOptions,
-  ConnectionLike,
   WorkflowClient,
   WorkflowClientOptions,
   WorkflowResultOptions,
@@ -165,7 +164,7 @@ export class TestWorkflowEnvironment {
   /**
    * Get an established {@link Connection} to the ephemeral server
    */
-  public readonly connection: ConnectionLike;
+  public readonly connection: Connection;
 
   /**
    * A {@link TestEnvClient} for interacting with the ephemeral server