Move monkeypatching of metadata 2.0 support to a more proper place

It was done in the support code for the wheel file format but it
affects metadata loading from all supported distribution types. Move
it to generic code.

twine/package.py

@@ -29,6 +29,18 @@
 from twine import wheel
 from twine import wininst
 
+# Monkeypatch Metadata 2.0 support
+metadata._VALID_METADATA_VERSIONS = [
+    "1.0",
+    "1.1",
+    "1.2",
+    "2.0",
+    "2.1",
+    "2.2",
+    "2.3",
+    "2.4",
+]
+
 DIST_TYPES = {
     "bdist_wheel": wheel.Wheel,
     "bdist_wininst": wininst.WinInst,

twine/wheel.py

@@ -14,17 +14,11 @@
 import os
 import re
 import zipfile
-from typing import List, Literal, Optional
-
-import packaging.metadata
+from typing import List, Optional
 
 from twine import distribution
 from twine import exceptions
 
-# Monkeypatch Metadata 2.0 support
-packaging.metadata._VALID_METADATA_VERSIONS = ["1.0", "1.1", "1.2", "2.0", "2.1", "2.2", "2.3", "2.4"]
-
-
 wheel_file_re = re.compile(
     r"""^(?P<namever>(?P<name>.+?)(-(?P<ver>\d.+?))?)
         ((-(?P<build>\d.*?))?-(?P<pyver>.+?)-(?P<abi>.+?)-(?P<plat>.+?)