Fix webengine remote debugging in Qt6

https://github.com/ankitects/anki/pull/2806

+ Enable remote debugging with run.bat, like in run. It doesn't allow
overriding - someone who better knows .bat scripts will need to handle
that if they need it.

run

@@ -7,6 +7,8 @@ export PYTHONPYCACHEPREFIX=out/pycache
 # define these as blank before calling the script if you want to disable them
 export ANKIDEV=${ANKIDEV-1}
 export QTWEBENGINE_REMOTE_DEBUGGING=${QTWEBENGINE_REMOTE_DEBUGGING-8080}
+export QTWEBENGINE_CHROMIUM_FLAGS=${QTWEBENGINE_CHROMIUM_FLAGS---remote-allow-origins=http://localhost:$QTWEBENGINE_REMOTE_DEBUGGING}
+
 # The pages can be accessed by, e.g. surfing to
 # http://localhost:40000/_anki/pages/deckconfig.html
 # Useful in conjunction with tools/web-watch for auto-rebuilding.

run.bat

@@ -4,6 +4,8 @@ pushd "%~dp0"
 set PYTHONWARNINGS=default
 set PYTHONPYCACHEPREFIX=out\pycache
 set ANKIDEV=1
+set QTWEBENGINE_REMOTE_DEBUGGING=8080
+set QTWEBENGINE_CHROMIUM_FLAGS=--remote-allow-origins=http://localhost:8080
 
 call tools\ninja pylib qt extract:win_amd64_audio || exit /b 1
 .\out\pyenv\scripts\python tools\run.py %* || exit /b 1