[roll] Roll fuchsia [session][inspect][input] Add an inspect pipeline stage

This stage will allow us to measure and ensure a smooth flow
of input events through the input pipeline.

This will allow closed-box debugging of the input event flow, such
as the ones in the quoted bugs.

Example use:

```
fx ffx inspect show \
  "core/session-manager/session:\:session/scene_manager"
```

Output is like this:

```
core/session-manager/session\:session/scene_manager:
  metadata:
    filename = fuchsia.inspect.Tree
    component_url = fuchsia-pkg://fuchsia.com/scene_manager#meta/scene_manager.cm
    timestamp = 62182195088
  payload:
    root:
      input_pipeline:
        input_pipeline_entry:
          events_count = 4
          last_generated_timestamp_ns = 36293071683
          last_seen_timestamp_ns = 36293838930
        input_pipeline_exit:
          events_count = 0
          last_generated_timestamp_ns = 0
          last_seen_timestamp_ns = 0
```

Original-Bug: 81262, 82593

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/568421
Original-Revision: 405bfdaad7d959fdfa90b8c37a0f3749f67491c2
GitOrigin-RevId: 0e2db7cd8564aa93e872fb7bcdc58aa280cf3b8b
Change-Id: Icdf7357d0e98256e34d540a6cdbe6c41c526b7a6