add icon to challenge achievements

Habitica/build.gradle

@@ -150,7 +150,7 @@ android {
         buildConfigField "String", "TESTING_LEVEL", "\"production\""
         resConfigs "en", "bg", "de", "en-rGB", "es", "fr", "hr-rHR", "in", "it", "iw", "ja", "ko", "lt", "nl", "pl", "pt-rBR", "pt-rPT", "ru", "tr", "zh", "zh-rTW"
 
-        versionCode 2629
+        versionCode 2632
         versionName "3.1"
     }
 

Habitica/res/layout/achievement_challenge_item.xml

@@ -7,15 +7,14 @@
     android:gravity="center_vertical"
     android:paddingTop="13dp"
     android:paddingBottom="13dp">
-    <TextView
+    <ImageView
         android:id="@+id/achievement_count_label"
         android:layout_width="40dp"
         android:layout_height="40dp"
         android:gravity="center"
         android:textColor="@color/text_ternary"
         style="@style/Body1"
-        android:background="@drawable/circle_offset"
-        tools:text="12"
+        android:src="@drawable/won_challenge_icon"
         android:layout_marginStart="35dp"
         android:layout_marginEnd="25dp"/>
     <TextView