adjust import style and references in client.dynamic

[junkmd]

THIS IS FOR drop_py2 PLAN! Please see #392.

Some import styles and references to module.object are redundant.
In addition, there are some points that are not a problem at runtime but raise errors or warnings in static analysis.

• For example, comtypes.COMError on line 30.
  When importing comtypes.automation, its "parent" comtypes are also loaded, so there is no problem at runtime, but since comtypes itself is not imported, static analysis raises an error.

comtypes/comtypes/client/dynamic.py

Lines 1 to 8 in 39d9e00

	import ctypes
	import comtypes.automation
	import comtypes.typeinfo
	import comtypes.client
	import comtypes.client.lazybind
	from comtypes import COMError, IUnknown, _is_object
	import comtypes.hresult as hres

comtypes/comtypes/client/dynamic.py

Lines 22 to 33 in 39d9e00

	def Dispatch(obj):
	# Wrap an object in a Dispatch instance, exposing methods and properties
	# via fully dynamic dispatch
	if isinstance(obj, _Dispatch):
	return obj
	if isinstance(obj, ctypes.POINTER(comtypes.automation.IDispatch)):
	try:
	tinfo = obj.GetTypeInfo(0)
	except (comtypes.COMError, WindowsError):
	return _Dispatch(obj)
	return comtypes.client.lazybind.Dispatch(obj, tinfo)
	return obj

Modernize the codebase by removing static analysis errors and import redundancies.

[junkmd]

I created this issue to serve as a "model case" for future good first issue that I will submit.

I will work on this.