Removes message arg from Hear, free performance (#93020)

## About The Pull Request

The first argument of `Hear` is `message`, the message heard

OR SO YOU'D THINK

Actually the first argument doesn't do anything but get overridden by
ALL implementations of `Hear`

No other uses as far as I and Ephe can tell. Removing it makes it a ton
easier to understand and gives us some free performance in radio code by
not rendering messages twice

## Changelog

🆑 Melbert
code: Removed some redundant code from core hearing code. Report if you
hear anything weird.
/🆑

code/modules/unit_tests/say.dm

@@ -125,9 +125,6 @@
 /datum/unit_test/speech/proc/handle_hearing(datum/source, list/hearing_args)
 	SIGNAL_HANDLER
 
-	// So it turns out that the `message` arg for COMSIG_MOVABLE_HEAR is super redundant and should probably
-	// be gutted out of both the Hear() proc and signal since it's never used
-	//TEST_ASSERT(hearing_args[HEARING_MESSAGE], "Handle hearing signal does not have a message arg")
 	TEST_ASSERT(hearing_args[HEARING_SPEAKER], "Handle hearing signal does not have a speaker arg")
 	TEST_ASSERT(hearing_args[HEARING_LANGUAGE], "Handle hearing signal does not have a language arg")
 	TEST_ASSERT(hearing_args[HEARING_RAW_MESSAGE], "Handle hearing signal does not have a raw message arg")
@@ -166,7 +163,7 @@
 	var/datum/client_interface/mock_client = new()
 	listener.mock_client = mock_client
 
-	RegisterSignal(speaker, COMSIG_MOB_SAY, PROC_REF(handle_speech)) //
+	RegisterSignal(speaker, COMSIG_MOB_SAY, PROC_REF(handle_speech))
 	RegisterSignal(speaker_radio, COMSIG_RADIO_NEW_MESSAGE, PROC_REF(handle_radio_hearing))
 
 	RegisterSignal(listener, COMSIG_MOVABLE_HEAR, PROC_REF(handle_hearing))