update minSdk to 24, cleanup code (#4014)

closes https://github.com/tuskyapp/Tusky/issues/2607
redo of https://github.com/tuskyapp/Tusky/pull/3593

app/src/main/java/com/keylesspalace/tusky/util/StatusParsingHelper.kt

@@ -18,7 +18,6 @@
 package com.keylesspalace.tusky.util
 
 import android.text.Html.TagHandler
-import android.text.SpannableStringBuilder
 import android.text.Spanned
 import androidx.core.text.parseAsHtml
 
@@ -36,31 +35,3 @@ fun String.parseAsMastodonHtml(tagHandler: TagHandler? = null): Spanned {
          * most status contents do, so it should be trimmed. */
         .trimTrailingWhitespace()
 }
-
-fun replaceCrashingCharacters(content: Spanned): Spanned {
-    return replaceCrashingCharacters(content as CharSequence) as Spanned
-}
-
-fun replaceCrashingCharacters(content: CharSequence): CharSequence? {
-    var replacing = false
-    var builder: SpannableStringBuilder? = null
-    val length = content.length
-    for (index in 0 until length) {
-        val character = content[index]
-
-        // If there are more than one or two, switch to a map
-        if (character == SOFT_HYPHEN) {
-            if (!replacing) {
-                replacing = true
-                builder = SpannableStringBuilder(content, 0, index)
-            }
-            builder!!.append(ASCII_HYPHEN)
-        } else if (replacing) {
-            builder!!.append(character)
-        }
-    }
-    return if (replacing) builder else content
-}
-
-private const val SOFT_HYPHEN = '\u00ad'
-private const val ASCII_HYPHEN = '-'