adding some start margin to the export filename label

app/src/main/res/layout/dialog_export_messages.xml

@@ -34,6 +34,7 @@
             android:id="@+id/export_messages_filename_label"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
+            android:layout_marginStart="@dimen/small_margin"
             android:text="@string/filename_without_json"
             android:textSize="@dimen/smaller_text_size" />