When get_lot_as_json without recursive, return "owner"

To distinguish between a lot's personal owner and those who own the lot through
inheritance, the `get_lot_as_json` function will return something like
```
"owners": ["owner1", "owner2"]
```
when called with recursion, and something like
```
"owner": "owner1"
```
when called without.

The distinction here is that "owner" MUST map to the lot's personal owner,
whereas "owners" is a list of all owners, including the personal owner.

src/lotman.cpp

@@ -1522,7 +1522,7 @@ int lotman_get_lot_as_json(const char *lot_name, const bool recursive, char **ou
             output_obj["owners"] = rp_vec_str.first;
         }
         else {
-            output_obj["owners"] = rp_vec_str.first[0]; // Only one owner, this is where it will be.
+            output_obj["owner"] = rp_vec_str.first[0]; // Only one owner, this is where it will be.
         }
 
         // Add parents according to recursive flag