hotfix for radio talking (#4769)

# About the pull request

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Hotfix for #4645 - removing the switch clause makes normal talk fall
through into radio speech and makes everyone talk on radio all the time


# Testing Photographs and Procedure
Very basic testing


# Changelog
:cl:
fix: Fixed people talking in radios all the time. Finally some quiet.
/:cl:

code/modules/mob/living/carbon/human/say.dm

@@ -141,9 +141,10 @@
 					used_radios += I
 					break // remove this if we EVER have two different intercomms with DIFFERENT frequencies IN ONE ROOM
 			else
-				var/earpiece = get_type_in_ears(/obj/item/device/radio)
-				if(earpiece)
-					used_radios += earpiece
+				if(message_mode != MESSAGE_MODE_LOCAL)
+					var/earpiece = get_type_in_ears(/obj/item/device/radio)
+					if(earpiece)
+						used_radios += earpiece
 
 		var/sound/speech_sound
 		var/sound_vol