Field Slip system test adjustments

[nimmolo]

Refactors the field_slips_test as integration tests. Should run faster and be just as effective.

Background:

With system tests, they're slow and we only really need them if we're testing JS.

[coveralls]

coverage: 94.397%. remained the same
when pulling 27ab49d on nimmo-system-test-class-selector-adjustments
into 977aeb9 on main.

[nimmolo]

Update: This PR does have some things we may want to keep:

• Adds identifying selector classes to the important links on Field Slips, so Capybara never has to use xpath. xpath selectors tend to be brittle if HTML is reorganized.
• Parens for method args is MO's Rubocop style.

[nimmolo]

@mo-nathan — I just converted your original short system tests to equally short integration tests, as we discussed a couple weeks ago. I think keeping the tests separate preserves your original intent.

Note the addition of selector classes to the templates, so we don't have to use XPATH selectors in our tests - much easier.

[nimmolo]

@mo-nathan I am realizing this will affect your #2160 Field Slip Forms PR.

I believe it is an improvement on the form HTML, particularly the selectors, and makes the tests less brittle. If you like, I'll be happy to check #2160 over and reconcile these changes with that PR.

[mo-nathan]

Looks good to me!

[nimmolo]

Ok thanks, I will merge. Just say the word and I'll either reconcile it with #2160, or offer suggestions - I realize this creates extra work on a long-running PR of yours and that you're probably not wanting any added confusion with it.