Use the location pointer for the Closest label

The Closest label was drawing location.north.fill. A north arrow reads as a
bearing — it implies direction of travel toward something, which is the wrong
idea for a label that means "this is the station nearest you". The plain
location pointer says where a place is without implying a heading, and it is
already the glyph the app's other location affordances draw in Settings and on
the map.

One constant, as before: StationLabelKind.closest.symbol. The badge, the Key
legend and both verdict symbols reference it, so nothing else needed touching.

The test that pins each label's glyph now expects "location"; its north-arrow
expectation was the only failure in the suite. The comment above the verdict
symbol still described a north arrow and now describes the pointer.

Also bumps CURRENT_PROJECT_VERSION 30 -> 31 for this device install round.

Tests: 278 pass.

Shared/FuelSavings.swift

@@ -457,7 +457,7 @@ struct FuelSavingsRankedStation: Equatable {
             switch self {
             case .bestValue: return "medal"
             case .cheapest: return "tag"
-            case .closest: return "location.north.fill"
+            case .closest: return "location"
             }
         }
     }