[LOOP-3477] display nothing for trend icon instead of a question mark icon (#391)

Author: nhamming

LoopTests/ViewModels/CGMStatusHUDViewModelTests.swift

@@ -130,7 +130,7 @@ class CGMStatusHUDViewModelTests: XCTestCase {
                                      wasUserEntered: true,
                                      isDisplayOnly: false)
 
-        XCTAssertEqual(viewModel.manualGlucoseTrendIconOverride, UIImage(systemName: "questionmark.circle"))
+        XCTAssertNil(viewModel.manualGlucoseTrendIconOverride)
         XCTAssertNil(viewModel.statusHighlight)
         XCTAssertEqual(viewModel.glucoseValueString, "90")
         XCTAssertNil(viewModel.trend)

LoopUI/ViewModel/CGMStatusHUDViewModel.swift

@@ -27,7 +27,7 @@ public class CGMStatusHUDViewModel {
 
     var glucoseTrendIcon: UIImage? {
         guard let manualGlucoseTrendIconOverride = manualGlucoseTrendIconOverride else {
-            return trend?.image ?? UIImage(systemName: "questionmark.circle")
+            return trend?.image
         }
         return manualGlucoseTrendIconOverride
     }
@@ -163,7 +163,7 @@ public class CGMStatusHUDViewModel {
     }
 
     func setManualGlucoseTrendIconOverride() {
-        manualGlucoseTrendIconOverride = storedStatusHighlight?.image ?? UIImage(systemName: "questionmark.circle")
+        manualGlucoseTrendIconOverride = storedStatusHighlight?.image
         glucoseTrendTintColor = storedStatusHighlight?.state.color ?? .glucoseTintColor
     }
 }

LoopUI/Views/GlucoseTrendHUDView.swift

@@ -19,7 +19,6 @@ public final class GlucoseTrendHUDView: BaseHUDView {
 
     @IBOutlet private weak var trendIcon: UIImageView! {
         didSet {
-            trendIcon.image = UIImage(systemName: "questionmark.circle")
             trendIcon.tintColor = .glucoseTintColor
         }
     }
@@ -31,6 +30,6 @@ public final class GlucoseTrendHUDView: BaseHUDView {
     }
 
     public func setIcon(_ icon: UIImage?) {
-        trendIcon.image = icon ?? UIImage(systemName: "questionmark.circle")
+        trendIcon.image = icon
     }
 }