task-amharic*: Migrate from fcitx4 to fcitx5
For task-amharic-*, they are now using fcitx 4.x. Considering that fcitx 4.x upstream support is now officially dead and upstream has archived related projects [1], we should move to use fcitx5's support instead.
This commit contains the following changes:
- fcitx -> fcitx5
- fcitx-table-amharic -> fcitx5-table-amharic
- fcitx gtk2/gtk3 frontend -> fcitx5 gtk2/gtk3/gtk4 frontend
- fcitx4 qt5 frontend -> fcitx5 qt5/qt6 frontend
- fcitx4 KDE config -> fcitx5 KDE config
Besides, the dependency to fcitx4 GTK config GUI tool is removed since the fcitx5 upstream is only providing a Qt/KDE frontend GUI config tool at this moment.
[1] https://lists.debian.org/debian-input-method/2024/10/msg00042.html
Bug-Debian: https://bugs.debian.org/1117873