feat: Expose required things for React Native auto tracing (#3144)

* feat: Expose required things for react native tracing

* ref: Only export what's needed from request

Author: jennmueng

packages/tracing/src/browser/index.ts

@@ -1 +1,6 @@
 export { BrowserTracing } from './browsertracing';
+export {
+  registerRequestInstrumentation,
+  RequestInstrumentationOptions,
+  defaultRequestInstrumentationOptions,
+} from './request';

packages/tracing/src/index.ts

@@ -7,8 +7,14 @@ const Integrations = { ...TracingIntegrations, BrowserTracing };
 export { Integrations };
 export { Span } from './span';
 export { Transaction } from './transaction';
-
+export {
+  registerRequestInstrumentation,
+  RequestInstrumentationOptions,
+  defaultRequestInstrumentationOptions,
+} from './browser';
 export { SpanStatus } from './spanstatus';
+export { IdleTransaction } from './idletransaction';
+export { startIdleTransaction } from './hubextensions';
 
 // We are patching the global object with our hub extension methods
 addExtensionMethods();