Remove defunct pywin32 license (nvaccess#15970)

By performing pip freeze in the NVDA virtual environment, it appears we no longer use or depend on the library pywin32 - nvaccess#9639

Pywin32 also has changed licence to the Python Software Foundation licence which is also included in our license file.

Therefore, we should remove this custom license from our licence.

copying.txt

@@ -1915,42 +1915,6 @@ the HTML Library software distribution is included in the file
 docs/license.html_lib.
 ```
 
-= Python Windows Extensions License =
-This applies to Python Windows extensions, available from http://sourceforge.net/projects/pywin32/
-
-```
-Unless stated in the specfic source file, this work is
-Copyright (c) 1994-2008, Mark Hammond 
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without 
-modification, are permitted provided that the following conditions 
-are met:
-
-Redistributions of source code must retain the above copyright notice, 
-this list of conditions and the following disclaimer.
-
-Redistributions in binary form must reproduce the above copyright 
-notice, this list of conditions and the following disclaimer in 
-the documentation and/or other materials provided with the distribution.
-
-Neither name of Mark Hammond nor the name of contributors may be used 
-to endorse or promote products derived from this software without 
-specific prior written permission. 
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
-IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
-TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
-PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR
-CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
-EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
-PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
-PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
-LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
-NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
-```
-
 = wxWindows Library License version 3.1 =
 This applies to wxPython, available from http://www.wxpython.org/