elixir sdk tests: no need to start exporter bc tests use pid exporter

Author: Tristan Sloughter

test/test_helper.exs

@@ -5,6 +5,6 @@ Application.put_env(:opentelemetry, :processors, [
   {:otel_batch_processor, %{scheduled_delay_ms: 1}}
 ])
 
-{:ok, _} = Application.ensure_all_started(:opentelemetry_exporter)
+{:ok, _} = Application.ensure_all_started(:opentelemetry)
 
 ExUnit.start()