Fix warnings in tests (don't use tidyselect, igraph deprecated features) + gh actions

[olivroy]

• use dplyr::all_of() and with igraph, mode instead of neimode. (

Various cleaning in tests to make the potential transition to testthat 3rd edition much easier (as expect_is is deprecated for testthat edition 3)

Edit: I also updated gh actions because they were not testing for r 4.3 and r 4.4