TST: Replace pywin32 with ctypes wrapper

We only use `pywin32` for one function, and while taking care of all the
wrapping is nice, it's easy to just take the information from the MSDN
docs [1] and pass it through `ctypes` instead.

This avoids the dependency entirely, helping to fix package conflicts
with pixi [2].

[1] https://learn.microsoft.com/en-us/windows/console/generateconsolectrlevent
[2] matplotlib#30877 (comment)

Author: QuLogic

lib/matplotlib/tests/test_backends_interactive.py

@@ -702,8 +702,11 @@ def _test_sigint_impl(backend, target_name, kwargs):
 
     def interrupter():
         if sys.platform == 'win32':
-            import win32api
-            win32api.GenerateConsoleCtrlEvent(0, 0)
+            from ctypes import windll, wintypes
+            GenerateConsoleCtrlEvent = windll.kernel32.GenerateConsoleCtrlEvent
+            GenerateConsoleCtrlEvent.argtypes = [wintypes.DWORD, wintypes.DWORD]
+            GenerateConsoleCtrlEvent.restype = wintypes.BOOL
+            GenerateConsoleCtrlEvent(0, 0)
         else:
             import signal
             os.kill(os.getpid(), signal.SIGINT)

pyproject.toml

@@ -146,7 +146,6 @@ test-extra = [
     "pandas!=0.25.0",
     "pikepdf",
     "pytz",
-    "pywin32; sys_platform == 'win32'",
     "xarray",
 ]