some osm tags not included

For https://www.openstreetmap.org/node/8671377598#map=19/49.40434/8.69222
only
```
{
"7": {
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
8.692216,
49.40434
]
},
"properties": {
"osm_id": 8671377598,
"osm_type": 1,
"distance": 0,
"category_ids": {
"528": {
"category_name": "vending_machine",
"category_group": "shops"
}
}
}
}
}
```
is returned without the osm_tag `vending=parking_tickets`

Are there only specific tags considered and returned?

Start by reproducing the response for OpenStreetMap node 8671377598 and compare its source tags with the returned properties. Then trace how openpoiservice selects OSM tags for the vending_machine category. Done means the handling of vending=parking_tickets is explained and, if its omission is unintended, the response behavior is corrected and verified.

Written by the indexing model from the issue text.