fix: correct radiation retrieval method and ensure monitor is cleared before startup

environment_driver.lua

@@ -1,6 +1,6 @@
 
 local function getValue()
-    return environment.getRadiationLevel().radiation
+    return environment.getRadiation().radiation
 end
 
 local function watch()

main.lua

@@ -83,8 +83,8 @@ local function run()
         sleep(1)
     end
 
-    monitor.clear();
     startUp();
+    monitor.clear();
     parallel.waitForAll(runMonitors, runDisplay)
 end