pass **kw args to arun_command in run_command_in_foreground

this makes the debug shell run in / rather than /snap/subiquity/whatever

subiquitycore/core.py

@@ -395,7 +395,7 @@ class Application:
 
         async def _run():
             await arun_command(
-                cmd, stdin=None, stdout=None, stderr=None)
+                cmd, stdin=None, stdout=None, stderr=None, **kw)
             screen.start()
             urwid.emit_signal(
                 screen, urwid.display_common.INPUT_DESCRIPTORS_CHANGED)