[roll] Roll fuchsia [power] Reformat Inspect for CPU power usage

Reformats the Inspect property located at selector
ThermalPolicy/state/throttle_history/*/cpu_power_usage.  The reformat is
to ensure we can select on the data without using a wildcard to match
all property values which presents problems for metrics filtering.

Previously, the histogram property name was an integer value
representing the CPU domain that the CPU power usage values inside the
histogram corresponded to. This meant that a wildcard must be used to
match any integer property name under the "cpu_power_usage" selector
path. Using the wildcard in this way is disallowed by metrics filtering
pipelines.

With this change, the "cpu_power_usage" selector path now instead
contains children nodes that are named after the CpuControlHandler node
that the CPU power usage readings correspond to. Each of these child
nodes then contains a histogram property called "hist". These properties
can now be selected by the path
.../cpu_power_usage/CpuControlHandler*:hist

Test: fx power-manager-tests
Test: Booted up the changes on an Astro and forced thermal throttling to
  take place. Verified Inspect showed data values in the expected
  format:
    "cpu_power_usage": {
      "CpuControlHandler (/dev/class/cpu-ctrl/000)": {
        "hist": {
          "buckets": [
    ...etc
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/565866
Original-Revision: 75e29c6d4494f34a9b68a590a87222c4c436b2a7
GitOrigin-RevId: 099c120ee66651c75fcbd4a8ba7cef95f7e89085
Change-Id: Ia1bd21647b2a59b6f9d21c25639bd4e34a740112