Fix leaks caused by mismatch of CFRelease/CFRetain with SecItemCopyMatching

src/native/libs/System.Security.Cryptography.Native.Apple/pal_keychain_ios.c

@@ -45,13 +45,11 @@ static int32_t EnumerateKeychain(CFStringRef matchType, CFArrayRef* pCertsOut)
         assert(result == NULL);
         status = noErr;
     }
-    else
-    {
+
     if (result != NULL)
     {
         CFRelease(result);
     }
-    }
 
     return status;
 }

src/native/libs/System.Security.Cryptography.Native.Apple/pal_keychain_macos.c

@@ -263,6 +263,11 @@ static bool IsCertInKeychain(CFTypeRef needle, SecKeychainRef haystack)
         ret = false;
     }
     
+    if (result != NULL)
+    {
+        CFRelease(result);
+    }
+
     CFRelease(itemMatch);
     CFRelease(searchList);
     CFRelease(query);