Fix TIPLOC in darwin-tiplocs to be a simple string, rather than an array

schemas/data-ingress/darwin-reference-data/darwin-tiplocs.json

@@ -38,7 +38,7 @@
                         "description": "CRS of the location"
                     },
                     "t": {
-                        "type": "array",
+                        "type": "string",
                         "description": "TIPLOC assigned to the location"
                     },
                     "n": {