android: qr scanner: add emoji to clipboard string

The string is not translated and might not be accessible for non-english
speakers, even though its relatively self-explanatory i think adding
this emoji makes it more accessible.

Author: f321x

contrib/ban_unicode.py

@@ -29,7 +29,7 @@
 UNICODE_WHITELIST = {
     "💬", "🗯", "⚠", chr(0xfe0f), "✓", "▷", "▽", "…", "•", "█", "™", "≈",
     "á", "é", "’",
-    "│", "─", "└", "├",
+    "│", "─", "└", "├", "📋",
 }
 
 exit_code = 0

electrum/gui/qml/android_res/layout/scanner_layout.xml

@@ -31,6 +31,6 @@
         android:layout_gravity="center|bottom"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="Paste from clipboard" />
+        android:text="Paste from clipboard 📋" />
 
 </FrameLayout>