fix: load trailing slash option from server even when there's no load function

[GingerAdonis]

While creating a test for #10475 I've noticed that the existing trailing-slash-server tests weren't actually using the server trailingSlash option. I've changed that which caused the tests to fail. The analyser skipped over this option when there's no load function. This PR includes both the changed test, and the fix for this test.

There might be a better approach, but this is what I came up with after digging in the code for 2 days.

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[dummdidumm]

Thank you! Since those PRs are closely related, could you incorporate the changes here into the other PR? You can create multiple changesets for one PR.

On the change itself: It's a bit unfortunate that we'd have to do a load just for this. An alternative might be to check for this edge case and add that config to a client load function instead. I haven't dug into how many things there would need to be changed, so if it's too much I'd be ok with the current solution.

[GingerAdonis]

Thank you! Since those PRs are closely related, could you incorporate the changes here into the other PR? You can create multiple changesets for one PR.

Will do!

On the change itself: It's a bit unfortunate that we'd have to do a load just for this. An alternative might be to check for this edge case and add that config to a client load function instead. I haven't dug into how many things there would need to be changed, so if it's too much I'd be ok with the current solution.

It's indeed unfortunate. I have only limited knowledge of the Kit codebase, but as far as I can tell that would be quite a lot of work. :(