Remove beta webtoon viewer split page

This had a bunch of issues around split pages not showing up properly so things
end up appearing to be missing while reading.
It'd be more worthwhile redoing the reader viewers than trying to get this to work
properly. It'd be better to just enable the split pages on download instead.

Closes #8433

(cherry picked from commit 94cba9324c872b1f0caa3f4d385266f190a9b114)

# Conflicts:
#	app/src/main/java/eu/kanade/presentation/more/settings/screen/SettingsReaderScreen.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderViewModel.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/reader/setting/ReaderPreferences.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonPageHolder.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonViewer.kt
#	core/src/main/java/tachiyomi/core/util/system/ImageUtil.kt

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

@@ -366,72 +366,6 @@ object ImageUtil {
 
     private fun splitImageName(filenamePrefix: String, index: Int) = "${filenamePrefix}__${"%03d".format(index + 1)}.jpg"
 
-    /**
-     * Check whether the image is a long Strip that needs splitting
-     * @return true if the image is not animated and it's height is greater than image width and screen height
-     */
-    fun isStripSplitNeeded(
-        imageStream: BufferedInputStream,
-        // SY -->
-        zip4jFile: ZipFile?,
-        zip4jEntry: FileHeader?,
-        // SY <--
-    ): Boolean {
-        if (isAnimatedAndSupported(imageStream)) return false
-
-        val options = extractImageOptions(
-            imageStream,
-            // SY -->
-            zip4jFile,
-            zip4jEntry,
-            // SY <--
-        )
-        val imageHeightIsBiggerThanWidth = options.outHeight > options.outWidth
-        val imageHeightBiggerThanScreenHeight = options.outHeight > optimalImageHeight
-        return imageHeightIsBiggerThanWidth && imageHeightBiggerThanScreenHeight
-    }
-
-    /**
-     * Split the imageStream according to the provided splitData
-     */
-    fun splitStrip(splitData: SplitData, streamFn: () -> InputStream): InputStream {
-        val bitmapRegionDecoder = getBitmapRegionDecoder(streamFn())
-            ?: throw Exception("Failed to create new instance of BitmapRegionDecoder")
-
-        logcat {
-            "WebtoonSplit #${splitData.index} with topOffset=${splitData.topOffset} " +
-                "splitHeight=${splitData.splitHeight} bottomOffset=${splitData.bottomOffset}"
-        }
-
-        try {
-            val region = Rect(0, splitData.topOffset, splitData.splitWidth, splitData.bottomOffset)
-            val splitBitmap = bitmapRegionDecoder.decodeRegion(region, null)
-            val outputStream = ByteArrayOutputStream()
-            splitBitmap.compress(Bitmap.CompressFormat.JPEG, 100, outputStream)
-            return ByteArrayInputStream(outputStream.toByteArray())
-        } catch (e: Throwable) {
-            throw e
-        } finally {
-            bitmapRegionDecoder.recycle()
-        }
-    }
-
-    fun getSplitDataForStream(
-        imageStream: InputStream,
-        // SY -->
-        zip4jFile: ZipFile?,
-        zip4jEntry: FileHeader?,
-        // SY <--
-    ): List<SplitData> {
-        return extractImageOptions(
-            imageStream,
-            // SY -->
-            zip4jFile,
-            zip4jEntry,
-            // SY <--
-        ).splitData
-    }
-
     private val BitmapFactory.Options.splitData
         get(): List<SplitData> {
             val imageHeight = outHeight