Remove confirm exit option

Redundant with predictive back, but also just sort of pointless since it doesn't help
with any sort of app state retention.

(cherry picked from commit 8f4bc71cf7b99fe0b0d2ea68dfca0140477686cc)

# Conflicts:
#	app/src/main/java/eu/kanade/presentation/more/settings/screen/SettingsGeneralScreen.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/main/MainActivity.kt

core/src/main/java/tachiyomi/core/util/system/ImageUtil.kt

@@ -446,7 +446,7 @@ object ImageUtil {
                     "$partCount parts @ ${optimalSplitHeight}px height per part"
             }
 
-            return mutableListOf<SplitData>().apply {
+            return buildList {
                 val range = 0 until partCount
                 for (index in range) {
                     // Only continue if the list is empty or there is image remaining