Enhancement: add Tag Editor items to features exported via gdal

[sduret]

Steps to reproduce

1. File -> Export -> Geospatial vector data
2. Choose a file type, and file name
3. Hit save

Actual behaviour

Currently the GeoJSON export fails (https://github.com/OpenOrienteering/mapper/issues/2314)

If I make an ESRI Shapefile and then load the files in QGIS, inspecting my features in QGIS doesn't show any of the metadata from the tag editor.

Expected behaviour

I'm creating a map and adding detail to certain features (e.g. names of roads, names of land holders) via the Tag Editor. I'd like for those items to be exported in my GeoJSON.

Configuration

Mapper Version: 0.9.5 Operating System: macOS Sequoia 15.2