improve CaptionDialog for small screens (#4831)

(or giant soft keyboards)

https://mastodon.social/@bewitchedmind/113703199056088283

Before / After

<img
src="https://github.com/user-attachments/assets/04d9f9b8-1041-4b1e-bff4-3665865a6016"
width="300"/>
<img
src="https://github.com/user-attachments/assets/f88bb67e-ecb0-460a-b22b-58cff5a4b754"
width="300"/>


This makes it also look a bit weird on large screens, but I found no
easy way to limit the size. Its now basically back to where it was in
Tusky 26.

closes https://github.com/tuskyapp/Tusky/issues/4832

app/src/main/java/com/keylesspalace/tusky/components/compose/dialog/CaptionDialog.kt

@@ -49,8 +49,13 @@ class CaptionDialog : DialogFragment() {
 
     override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
         val localId = arguments?.getInt(LOCAL_ID_ARG) ?: error("Missing localId")
+        val inset = requireContext().resources.getDimensionPixelSize(R.dimen.caption_dialog_inset)
         return MaterialAlertDialogBuilder(requireContext())
             .setView(createView(savedInstanceState))
+            .setBackgroundInsetTop(inset)
+            .setBackgroundInsetEnd(inset)
+            .setBackgroundInsetBottom(inset)
+            .setBackgroundInsetStart(inset)
             .setPositiveButton(android.R.string.ok) { _, _ ->
                 listener.onUpdateDescription(localId, binding.imageDescriptionText.text.toString())
             }