Fedora does not have unijoy Bangla keyboard layout files in m17n. So they need to be manually copied.
Copy bn-unijoy.mim
to /usr/share/m17n/
Copy bn-unijoy.png
to /usr/share/m17n/icons/
Or run the following:
cd /path/to/this/dir
sudo cp ./bn-unijoy.mim /usr/share/m17n/
sudo cp ./bn-unijoy.png /usr/share/m17n/icons/
Then run:
ibus-daemon -xdr