bug#54562: 28.0.91; Emoji sequence not composed

[Po Lu]

The following Emoji does not display correctly:

  7⃣️

In other programs, it displays as the digit "7" inside a square, but
inside Emacs it displays as the digit "7", followed by the blue square,
and an empty hollow black square.

In GNU Emacs 28.0.91 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo version 
1.17.4, Xaw3d scroll bars)
 of 2022-02-08 built on trinity
Repository revision: 82e74e4559b8becd44f3e7ac0134e2baddd69921
Repository branch: emacs-28
Windowing system distributor 'The X.Org Foundation', version 11.0.12014000
System Description: Fedora Linux 35 (Workstation Edition)

Configured using:
 'configure --with-x-toolkit=lucid --with-native-compilation
 --cache-file=/tmp/ccache'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LCMS2 LIBSELINUX LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY
PDUMPER PNG RSVG SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11
XAW3D XDBE XIM XPM LUCID ZLIB

Important settings:
  value of $LANG: en_GB.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix