Remove per-category display mode

There seems to be little value in this feature, and juggling flag masks is annoying.
Per-category sorting is still a thing, but could be refactored away from the flag in the feature.

app/src/main/java/eu/kanade/presentation/library/LibrarySettingsDialog.kt

@@ -29,7 +29,6 @@ import eu.kanade.tachiyomi.ui.library.LibrarySettingsScreenModel
 import tachiyomi.domain.category.model.Category
 import tachiyomi.domain.library.model.LibraryDisplayMode
 import tachiyomi.domain.library.model.LibrarySort
-import tachiyomi.domain.library.model.display
 import tachiyomi.domain.library.model.sort
 import tachiyomi.domain.library.service.LibraryPreferences
 import tachiyomi.domain.manga.model.TriStateFilter
@@ -43,7 +42,7 @@ import tachiyomi.presentation.core.components.SortItem
 fun LibrarySettingsDialog(
     onDismissRequest: () -> Unit,
     screenModel: LibrarySettingsScreenModel,
-    category: Category,
+    category: Category?,
 ) {
     TabbedDialog(
         onDismissRequest = onDismissRequest,
@@ -67,7 +66,6 @@ fun LibrarySettingsDialog(
                     screenModel = screenModel,
                 )
                 2 -> DisplayPage(
-                    category = category,
                     screenModel = screenModel,
                 )
             }
@@ -146,7 +144,7 @@ private fun ColumnScope.FilterPage(
 
 @Composable
 private fun ColumnScope.SortPage(
-    category: Category,
+    category: Category?,
     screenModel: LibrarySettingsScreenModel,
 ) {
     val sortingMode = category.sort.type
@@ -179,10 +177,10 @@ private fun ColumnScope.SortPage(
 
 @Composable
 private fun ColumnScope.DisplayPage(
-    category: Category,
     screenModel: LibrarySettingsScreenModel,
 ) {
     HeadingItem(R.string.action_display_mode)
+    val displayMode by screenModel.libraryPreferences.libraryDisplayMode().collectAsState()
     listOf(
         R.string.action_display_grid to LibraryDisplayMode.CompactGrid,
         R.string.action_display_comfortable_grid to LibraryDisplayMode.ComfortableGrid,
@@ -191,12 +189,12 @@ private fun ColumnScope.DisplayPage(
     ).map { (titleRes, mode) ->
         RadioItem(
             label = stringResource(titleRes),
-            selected = category.display == mode,
-            onClick = { screenModel.setDisplayMode(category, mode) },
+            selected = displayMode == mode,
+            onClick = { screenModel.setDisplayMode(mode) },
         )
     }
 
-    if (category.display != LibraryDisplayMode.List) {
+    if (displayMode != LibraryDisplayMode.List) {
         Row(
             modifier = Modifier
                 .fillMaxWidth()