Utilize normal fallback for homescreen icons.

app/src/main/java/org/thoughtcrime/securesms/util/DrawableUtil.java

@@ -0,0 +1,22 @@
+package org.thoughtcrime.securesms.util;
+
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.drawable.Drawable;
+
+import androidx.annotation.NonNull;
+
+public final class DrawableUtil {
+
+  private DrawableUtil() {}
+
+  public static @NonNull Bitmap toBitmap(@NonNull Drawable drawable, int width, int height) {
+    Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
+    Canvas canvas = new Canvas(bitmap);
+
+    drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
+    drawable.draw(canvas);
+
+    return bitmap;
+  }
+}