Don't null-assert value as it might not be set yet

app/src/main/java/com/frostnerd/smokescreen/fragment/DnsRuleFragment.kt

@@ -540,8 +540,9 @@ class DnsRuleFragment : Fragment() {
     private fun updateRuleCountTitle() {
          activity?.runOnUiThread {
              (activity as AppCompatActivity?)?.supportActionBar?.subtitle = if(getPreferences().dnsRulesEnabled) {
-                 val formattedString = getPreferences().numberFormatter.format(totalRuleCount ?: 0)
-                 resources.getQuantityString(R.plurals.window_dnsrules_subtitle, totalRuleCount!!.toInt(), formattedString)
+                 val ruleCount = totalRuleCount ?: 0
+                 val formattedString = getPreferences().numberFormatter.format(ruleCount)
+                 resources.getQuantityString(R.plurals.window_dnsrules_subtitle, ruleCount.toInt(), formattedString)
              } else null
         }
     }