Ensure we install ibus 1.5.19-4+deb10u1.0tails1 even though its version number is lower than 1.5.19-4.0tails3 (refs: #17144)

We can drop this once the APT overlay suite that introduces
1.5.19-4+deb10u1.0tails1 (bugfix-17144-ibus-security) is merged into our
"testing" APT suite during the 4.0 release process: this will replace the now
obsolete 1.5.19-4.0tails3 packages with the updated
1.5.19-4+deb10u1.0tails1 ones.