Add a clear all button to recent searches

Lets users wipe their whole search history at once from the recent
searches section header, as per the designs.

ElementX/Sources/Screens/SearchScreen/SearchScreenModels.swift

@@ -52,6 +52,7 @@ enum SearchScreenViewAction: CustomStringConvertible {
     case selectRoom(roomID: String)
     case selectMessage(roomID: String, eventID: String)
     case removeBreadcrumb(SearchScreenBreadcrumb)
+    case clearBreadcrumbs
     case reachedTop
     case reachedBottom
     case cancel
@@ -63,6 +64,7 @@ enum SearchScreenViewAction: CustomStringConvertible {
         case .selectRoom(let roomID): "selectRoom(\(roomID))"
         case .selectMessage(let roomID, let eventID): "selectMessage(\(roomID), \(eventID))"
         case .removeBreadcrumb: "removeBreadcrumb"
+        case .clearBreadcrumbs: "clearBreadcrumbs"
         case .reachedTop: "reachedTop"
         case .reachedBottom: "reachedBottom"
         case .cancel: "cancel"

ElementX/Sources/Screens/SearchScreen/SearchScreenViewModel.swift

@@ -149,6 +149,8 @@ class SearchScreenViewModel: SearchScreenViewModelType, SearchScreenViewModelPro
             actionsSubject.send(.presentRoom(roomID: roomID, eventID: eventID))
         case .removeBreadcrumb(let breadcrumb):
             removeBreadcrumb(breadcrumb)
+        case .clearBreadcrumbs:
+            userSettings.searchBreadcrumbs = []
         case .reachedTop:
             if state.bindings.searchMode == .rooms {
                 updateVisibleRange(edge: .top)

ElementX/Sources/Screens/SearchScreen/View/SearchScreen.swift

@@ -209,8 +209,19 @@ struct SearchScreen: View {
                     }
                 }
             } header: {
-                Text(UntranslatedL10n.screenSearchRecentSearches)
-                    .compoundListSectionHeader()
+                HStack(spacing: 8) {
+                    Text(UntranslatedL10n.screenSearchRecentSearches)
+                        .compoundListSectionHeader()
+                    
+                    Spacer()
+                    
+                    // The compound text link style has no accent colour variant.
+                    Button { context.send(viewAction: .clearBreadcrumbs) } label: {
+                        Text(L10n.actionClearAll)
+                            .font(.compound.bodyMDSemibold)
+                            .foregroundStyle(.compound.textActionAccent)
+                    }
+                }
             }
         }
         .compoundList(.plain)