conversation: always show back arrow

Since we have the welcome view we can always display the back arrow.
GitLab: #1421

Change-Id: Ie3fd30ee99ee4689df23b9499f2e4d6a7b07443b

jami-android/app/src/main/java/cx/ring/fragments/ConversationFragment.kt

@@ -304,9 +304,9 @@ class ConversationFragment : BaseSupportFragment<ConversationPresenter, Conversa
                 scrollToEnd()
             }
             setHasOptionsMenu(true)
-            if (!DeviceUtils.isTablet(requireContext())) {
-                binding.toolbar.setNavigationIcon(androidx.appcompat.R.drawable.abc_ic_ab_back_material)
-                binding.toolbar.setNavigationOnClickListener { activity?.onBackPressedDispatcher?.onBackPressed() }
+            binding.toolbar.setNavigationIcon(androidx.appcompat.R.drawable.abc_ic_ab_back_material)
+            binding.toolbar.setNavigationOnClickListener {
+                activity?.onBackPressedDispatcher?.onBackPressed()
             }
             binding.root
         }