Switch libvips to libvips-dev dependency

[wakproductions]

Context

Attempt at fixing the following error in CI:

Error:
Spina::Admin::SearchingMediaLibraryTest#test_searching_for_a_specific_file:
LoadError: Could not open library 'vips.so.42': vips.so.42: cannot open shared object file: No such file or directory.
Could not open library 'libvips.so.42': libvips.so.42: cannot open shared object file: No such file or directory

See similar issue: loomio/loomio#9492

Changes proposed in this pull request

Tweak dependency in test setup

[wakproductions]

A few of the Capybara tests seem to be flaky. When I run locally sometimes I get errors, sometimes it passes. Running sudo apt install libvips-dev fixed the particular lipvips.so.42 error in my local environment and seems to have worked here as well. However, there are some new test failures (my guess is flaky tests) that popped up and I don't know how to initiate a manual rerun of the Github Actions workflow. The rerun button is not appearing on my screen.

[Bramjetten]

Not applicable anymore