Back out "Fixes NSDataBigString length calculation" (#46011)

Summary:
Pull Request resolved: #46011

Backing out D58561775 in the meantime while we are trying to do proper fix in Hermes engine D61058869

Changelog: [Internal]
Temporarily revert this diff #44900 while we wait for #45966 to land

Reviewed By: makovkastar

Differential Revision: D61246120

fbshipit-source-id: 8c205efe9d29cd34f24676c4a48d55f0493d73ab

packages/react-native/React/CxxBridge/NSDataBigString.mm

@@ -34,8 +34,8 @@
 
 NSDataBigString::NSDataBigString(NSData *data)
 {
+  m_length = [data length];
   m_data = ensureNullTerminated(data);
-  m_length = MAX([m_data length], 1) - 1;
 }
 
 } // namespace facebook::react