feat(typing): Remove "libs" from pyright exclude and fix typing errors (#26423)

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

api/libs/gmpy2_pkcs10aep_cipher.py

@@ -27,7 +27,7 @@ import gmpy2  # type: ignore
 from Crypto import Random
 from Crypto.Signature.pss import MGF1
 from Crypto.Util.number import bytes_to_long, ceil_div, long_to_bytes
-from Crypto.Util.py3compat import _copy_bytes, bord
+from Crypto.Util.py3compat import bord
 from Crypto.Util.strxor import strxor
 
 
@@ -72,7 +72,7 @@ class PKCS1OAepCipher:
         else:
             self._mgf = lambda x, y: MGF1(x, y, self._hashObj)
 
-        self._label = _copy_bytes(None, None, label)
+        self._label = bytes(label)
         self._randfunc = randfunc
 
     def can_encrypt(self):
@@ -120,7 +120,7 @@ class PKCS1OAepCipher:
         # Step 2b
         ps = b"\x00" * ps_len
         # Step 2c
-        db = lHash + ps + b"\x01" + _copy_bytes(None, None, message)
+        db = lHash + ps + b"\x01" + bytes(message)
         # Step 2d
         ros = self._randfunc(hLen)
         # Step 2e