Improve `Awake` auto-instrumentation quality

[bitsandfoxes]

Currently, when opted-into, the SDK will auto-instrument awake calls.

Issue 1

This can get quite noisy. See 109 Awake instances within Trace View and that is just with 2 MonoBehaviours on each GameObject.
A possible solution would be to group all auto-instrumented awake calls together.

Issue 2

This follows Issue 1. Creating a manual span inside Awake causes it be be the parent of all subsequent Awake calls. See here and here.
If awake calls are already grouped together then there is no need to have them look up GetSpan to set the parent but they could refer to their "fixed" parent.