fix: improve TagPigeon export to support ISO 14443 NFC tags on Android

[yakupkahraman]

I encountered an issue while working with NFC cards that are not NDEF compatible but follow the ISO 14443 standard. When trying to read data from such tags using the nfc_manager package on Android, the output was "instance of TagPigeon" instead of the actual tag data.

To fix this, I exported pigeon.g.dart properly to enable direct access to the tag's low-level data, allowing correct handling and parsing of ISO 14443 tags.

This change improves compatibility with a wider range of NFC tags that are commonly used but not NDEF formatted.

For example, to get the tag ID, you can now do:

_id = (tag.data as TagPigeon).id.toString();

[iassal]

@okadan Can you please take a look?