Honour multi keypress timeout for NVDA key (#17219)

Fix-up of #12049 

Summary of the issue:
When implementing multi keypress timeout in #12049, the timeout for double press of NVDA key (to execute native function) was not honoured.

Description of user facing changes
Multiple key press timeout will now be honoured also for double press of NVDA key.

Description of development approach
Replace the hard-coded value 0.5 with the config value.

source/keyboardHandler.py

@@ -2,7 +2,7 @@
 # A part of NonVisual Desktop Access (NVDA)
 # This file is covered by the GNU General Public License.
 # See the file COPYING for more details.
-# Copyright (C) 2006-2023 NV Access Limited, Peter Vágner, Aleksey Sadovoy, Babbage B.V., Cyrille Bougot
+# Copyright (C) 2006-2024 NV Access Limited, Peter Vágner, Aleksey Sadovoy, Babbage B.V., Cyrille Bougot
 
 """Keyboard support"""
 
@@ -203,7 +203,10 @@ def internal_keyDownEvent(vkCode, scanCode, extended, injected):
 			or (
 				keyCode == lastNVDAModifier
 				and lastNVDAModifierReleaseTime
-				and time.time() - lastNVDAModifierReleaseTime < 0.5
+				and (
+					time.time() - lastNVDAModifierReleaseTime
+					< config.conf["keyboard"]["multiPressTimeout"] / 1000
+				)
 			)
 		):
 			# The user wants the key to serve its normal function instead of acting as an NVDA modifier key.