Fix Pages filter when URL has a trailing slash

[Wonderfall]

This fixes #606 as discussed there. It's not uncommon for URLs to have a trailing slash and this format is used for instance by Ghost CMS; thus it can cause issues with the way Umami clears URLs for its filtering function (requests do not have a trailing slash so they return empty results).

Tried this (very) small change myself and everything seems fine!

EDIT: After some thinking I think it was there in the first place to prevent mixing up trail & non-trail URLs. Normally this shouldn't be an issue as it should be properly handled by the website itself (in case of Ghost, it redirects non-slash to slash).

Don't hesitate to close this PR if you think there's a better way to handle this:

• For instance, Umami could become "slash agnostic" and return results for both slash & non-slash
• But now it's defaulting to non-slash, which breaks page filter for some of us

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