TC-TIMESYNC-2.2: Add missing step (#29416)

* TC-TIMESYNC-2.2: Add missing step

* Update src/python_testing/TC_TIMESYNC_2_2.py

* Update src/python_testing/TC_TIMESYNC_2_2.py

Co-authored-by: Boris Zbarsky <bzbarsky@apple.com>

---------

Co-authored-by: Boris Zbarsky <bzbarsky@apple.com>

src/python_testing/TC_TIMESYNC_2_2.py

@@ -63,6 +63,7 @@ async def test_TC_TIMESYNC_2_2(self):
                             "Granularity out of expected range")
         asserts.assert_not_equal(granularity_dut, time_cluster.Enums.GranularityEnum.kNoTimeGranularity)
 
+        self.print_step(4, "Read UTC time")
         th_utc = utc_time_in_matter_epoch()
         utc_dut = await self.read_ts_attribute_expect_success(endpoint=endpoint, attribute=attributes.UTCTime)
         asserts.assert_is_not(utc_dut, NullValue, "Received null value for UTCTime after set")
@@ -72,6 +73,12 @@ async def test_TC_TIMESYNC_2_2(self):
             tolerance = timedelta(minutes=1)
         compare_time(received=utc_dut, utc=th_utc, tolerance=tolerance)
 
+        self.print_step(5, "Read time source")
+        if self.check_pics("TIMESYNC.S.A0002"):
+            source = await self.read_ts_attribute_expect_success(endpoint=endpoint, attribute=attributes.TimeSource)
+            if utc_dut_initial is NullValue:
+                asserts.assert_equal(source, Clusters.Objects.TimeSynchronization.Enums.TimeSourceEnum.kAdmin)
+
 
 if __name__ == "__main__":
     default_matter_test_main()