Zim can't find dependencies for plugin in PATH in Windows OS

[mquan86]

Describe the bug
In Windows OS, any plugin has dependencies is failed to enable even the dependencies already in PATH.

To Reproduce

1. Windows OS
2. Install dependencies and make sure it is set in PATH
3. In Zim > Go to Preference to enable any plugins that require dependencies (for example "Insert diagram" which requires GraphViz)
4. Can't enable plugin as the dependencies is failed to load

Expected behavior
Should allow to enable plugin as dependencies is available in PATH

Screenshots

Environment (please complete the following information):

• Version 0.75.1 (install as portable mode - not sure if that trigger the bug?)
• OS: Windows 10

Additional context
Below is the code in Zim for lookup the dependences in PATH and it should see all the exe, bat... in PATH

zim-desktop-wiki/zim/applications.py

Lines 217 to 224 in 2d2970f

	elif os.name == 'nt':
	# Check executable extensions from windows environment
	extensions = _split_environ_list(os.environ.get('PATHEXT', '.com;.exe;.bat;.cmd'))
	for dir in _split_environ_list(os.environ.get('PATH')):
	for ext in extensions:
	file = SEP.join((dir, cmd + ext))
	if os.path.isfile(file) and os.access(file, os.X_OK):
	return file

Workaround: add a execution Windows Batch file (example dot.bat) to same folder of Zim will passed the dependencies requirement, however, there is another bug related to it as well in #2261