enable first_inference_latency (first_inference+time_to_inference) (#14829)

* add time_to_first_inference_result KPI as sum of inf latency values

* append unit time after the value

tested locally, worked

* Revert "append unit time after the value"

This reverts commit 428b8cafdc.

* remove metric

* revert 42dd271c3b

* enable { SCOPED_TIMER(first_inference_latency); }

* enable first_inference_latency

tested locally, it works

* remove trailing whitespace

Co-authored-by: Daria Ilina <daria.krupnova@intel.com>

tests/time_tests/scripts/run_timetest.py

@@ -55,7 +55,6 @@ def aggregate_stats(stats: dict):
                         "stdev": statistics.stdev(duration_list) if len(duration_list) > 1 else 0}
             for step_name, duration_list in stats.items()}
 
-
 def prepare_executable_cmd(args: dict):
     """Generate common part of cmd from arguments to execute"""
     return [