Snapd incompatible with fish, breaking x2go

[Lukas Katthaen]

I am using Ubuntu 20.04 LTS.

The current version of the 'snapd' package (snapd 2.54.2+20.04ubuntu2) includes the file
/usr/share/fish/vendor_conf.d/snapd.fish
which uses the fish-command 'fish_add_path'. That was introduced in 'fish 3.2.0', but 20.04 currently includes 'fish 3.1.0-1.2', which does not know that command.
(Check: try 'source /usr/share/fish/vendor_conf.d/snapd.fish' from fish)

For some reason this does not cause an error in normal operation.

However, when I try to logon the computer from remote via x2go (package x2goserver), then it reports an error at that place and the connection fails.

The error did not exist in 'snapd 2.51.1+20.04ubuntu2'. The change was made in this
https://github.com/snapcore/snapd/commit/f9dd306a07bdac8f0d42c6bb2791033a5b31d85e
commit.