feat: show room avatar when is DM

app/src/main/java/ru/risdeveau/pixeldragon/api/Server.kt

@@ -1,7 +1,6 @@
 /*
  * Created by sweetbread
  * Copyright (c) 2025. All rights reserved.
- * Last modified 03.03.2025, 15:40
  */
 
 package ru.risdeveau.pixeldragon.api
@@ -28,9 +27,11 @@ suspend fun getHomeserver(url: String): String? {
     return homeserver
 }
 
-fun mxcToUrl(mxc: String): String {
-    val pattern = Regex("mxc://([-a-zA-Z0-9@:%._+~#=]{1,256}\\.[a-zA-Z0-9()]{1,6})/([a-zA-Z]+)")
+fun mxcToUrl(mxc: String): String? {
+    val pattern = Regex("mxc://([-a-zA-Z0-9@:%._+~#=]{1,256}\\.[a-zA-Z0-9()]{1,6})/([a-zA-Z0-9]+)")
     val match = pattern.find(mxc)
 
+    if ((match?.groupValues[1] == null) or (match?.groupValues[2] == null)) return null
+
     return "$homeserver/_matrix/client/v1/media/download/${match?.groupValues[1]}/${match?.groupValues[2]}"
 }