SearchResults: Fix how running searches can be cancelled

Search results are wiped when the user switches to a new tab in the
app, but this should only be executed when the search is running.

Fortunately, just tracking the ProgressView's status should fix this
problem.

Signed-off-by: kingbri <bdashore3@gmail.com>

Ferrite/Views/SearchResultsView.swift

@@ -61,7 +61,7 @@ struct SearchResultsView: View {
         }
         .onChange(of: navModel.selectedTab) { tab in
             // Cancel the search if tab is switched
-            if tab != .search, isSearching {
+            if tab != .search, isSearching, navModel.showSearchProgress {
                 scrapingModel.runningSearchTask?.cancel()
                 dismissSearch()
             }