pydevd: Fix up prefix of attach shared library for Windows (#1939)

Follow-up to #1917, which changed the prefix for Windows. The crux of that contribution was about enabling attaching on Sillicon Mac (in fact, it came from my colleagues at Zed Industries). This however broke .dll lookup per zed-industries/zed#35640 (comment)

Author: osiewicz

src/debugpy/_vendored/pydevd/pydevd_tracing.py

@@ -250,7 +250,9 @@ def get_python_helper_lib_filename():
         else:
             suffix = suffix_32
 
-        if IS_WINDOWS or IS_MAC:  # just the extension changes
+        if IS_WINDOWS:  # just the extension changes
+            prefix = "attach_"
+        elif IS_MAC:
             prefix = "attach"
             suffix = ""
         elif IS_LINUX:  #