Add sensor unit mapping to NIC VEEPROM accessor.

GetSensorUnit, is added to the Accessor interface to retrieve the unit for a given NIC telemetry sensor. New SensorUnit types are also added to the sensor proto to support the NIC telemetry units.

Tested: https://fusion2.corp.google.com/invocations/b36d260c-3a2c-459b-bc7a-077748a0e4d0/targets
PiperOrigin-RevId: 846684788
Change-Id: Ic273740b7344a51420c0af197abd70809d3b4495

gbmcweb

diff --git a/gbmcweb b/gbmcweb
index c407e9f..d08b360 160000
--- a/gbmcweb
+++ b/gbmcweb
@@ -1 +1 @@
-Subproject commit c407e9f5504b59ca61cb544cdb3717cd721da736
+Subproject commit d08b360b57de9c43217cd8588d4d7bd5c7a50d20