Revert "fix TypeError: channel.execCallbacks[message.id] is not a function"

This reverts commit 331239de05.

This commit caused the blur event from the editor to fire after the saveNow()
callback had run, which broke the reviewer when returning from editcurrent.
Reverting for now, as the actual error is harmless AFAICT.

aqt/webview.py

@@ -63,8 +63,7 @@ class AnkiWebPage(QWebEnginePage):
         return False
 
     def _onCmd(self, str):
-        from aqt import mw
-        mw.progress.timer(1, lambda: self._onBridgeCmd(str), False)
+        self._onBridgeCmd(str)
 
 # Main web view
 ##########################################################################