tegaki-zinnia-japanese shouldn't be a dependency after handwriting support was removed

The Mozc packages shouldn't depend on tegaki-zinnia-japanese, a 26.1 MB handwriting support package, after handwriting support was removed from Mozc ( https://github.com/google/mozc/issues/477#issuecomment-739475097 ). The tegaki-zinnia project is also unmaintained ( https://github.com/tegaki/tegaki/issues/13#issuecomment-301248025 ).

1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu

$ lsb_release -rd
Description: Ubuntu Hirsute Hippo (development branch)
Release: 21.04

2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center

$ apt-cache policy mozc-utils-gui
mozc-utils-gui:
  Installed: 2.26.4220.100+dfsg-4ubuntu2
  Candidate: 2.26.4220.100+dfsg-4ubuntu2
  Version table:
 *** 2.26.4220.100+dfsg-4ubuntu2 500
        500 http://archive.ubuntu.com/ubuntu hirsute/universe amd64 Packages
        100 /var/lib/dpkg/status
$ apt-cache policy ibus-mozc
ibus-mozc:
  Installed: 2.26.4220.100+dfsg-4ubuntu2
  Candidate: 2.26.4220.100+dfsg-4ubuntu2
  Version table:
 *** 2.26.4220.100+dfsg-4ubuntu2 500
        500 http://archive.ubuntu.com/ubuntu hirsute/main amd64 Packages
        100 /var/lib/dpkg/status

3) What you expected to happen

I should not have to install the tegaki-zinnia-japanese package when I install Mozc. I shouldn't see that package in the dependency list:

$ apt-cache depends ibus-mozc
ibus-mozc
  Depends: libabsl20200923
  Depends: libc6
  Depends: libglib2.0-0
  Depends: libibus-1.0-5
  Depends: libprotobuf23
  Depends: libstdc++6
  Depends: libxcb-xfixes0
  Depends: libxcb1
  Depends: mozc-data
  Depends: mozc-server
  Depends: ibus
    ibus:i386
  Suggests: mozc-utils-gui

$ apt-cache depends mozc-utils-gui
mozc-utils-gui
  Depends: libabsl20200923
  Depends: libc6
  Depends: libgcc-s1
  Depends: libqt5core5a
 |Depends: libqt5gui5
  Depends: libqt5gui5-gles
  Depends: libqt5widgets5
  Depends: libstdc++6
  Depends: mozc-data
  Recommends: mozc-server
  Suggests: <ibus-qt5>

4) What happened instead

tegaki-zinnia-japanese is depended upon and I see the following:

$ apt-cache depends ibus-mozc
ibus-mozc
  Depends: libabsl20200923
  Depends: libc6
  Depends: libglib2.0-0
  Depends: libibus-1.0-5
  Depends: libprotobuf23
  Depends: libstdc++6
  Depends: libxcb-xfixes0
  Depends: libxcb1
  Depends: mozc-data
  Depends: mozc-server
  Depends: ibus
    ibus:i386
  Depends: tegaki-zinnia-japanese
  Suggests: mozc-utils-gui

$ apt-cache depends mozc-utils-gui
mozc-utils-gui
  Depends: libabsl20200923
  Depends: libc6
  Depends: libgcc-s1
  Depends: libqt5core5a
 |Depends: libqt5gui5
  Depends: libqt5gui5-gles
  Depends: libqt5widgets5
  Depends: libstdc++6
  Depends: mozc-data
  Depends: tegaki-zinnia-japanese
  Recommends: mozc-server
  Suggests: <ibus-qt5>