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.

FuelBoardTests/Tests/FuelBoardSharedTests/FuelSavingsTests.swift

@@ -368,7 +368,7 @@ final class KeySheetContentTests: XCTestCase {
     func testStationLabelKindsUseTheirRecommendedSymbols() {
         XCTAssertEqual(StationLabelKind.bestValue.symbol, "medal")
         XCTAssertEqual(StationLabelKind.cheapest.symbol, "tag")
-        XCTAssertEqual(StationLabelKind.closest.symbol, "location.north.fill")
+        XCTAssertEqual(StationLabelKind.closest.symbol, "location")
         // No trophy: "Top" is gone. One state, one label.
         XCTAssertFalse(StationLabelKind.allCases.map(\.symbol).contains("trophy"))
     }