sensors: don't pass excess conn handler

We don't need to pass connection handler to setInitialProperties method
since it already part of the sensor class.

Tested: no changes in behaviour.
Signed-off-by: Andrei Kartashev <a.kartashev@yadro.com>
Change-Id: Icaaccbeaf14e22648a6a1bce381f0f0a606b0ddd
diff --git a/src/ExternalSensor.cpp b/src/ExternalSensor.cpp
index 3401ac4..5fba9b4 100644
--- a/src/ExternalSensor.cpp
+++ b/src/ExternalSensor.cpp
@@ -60,7 +60,7 @@
 
     association =
         objectServer.add_interface(objectPath, association::interface);
-    setInitialProperties(conn, sensorUnits);
+    setInitialProperties(sensorUnits);
 
     if constexpr (debug)
     {