[openstreetmap/openstreetmap-website] Remove `file_exists` gem (PR #6334)

[rkoeze]

### Description
The file_exists gem [was originally added](https://github.com/til/openstreetmap-website/commit/c68fa8f8f5a89213aa22920edc72170093c5abbe) to support `File.exists?`, which was deprecated in Ruby 3.2 but still used by version 0.4.7 of the oauth gem. Since `File.exists?` was removed in version [0.5.0](https://github.com/oauth-xx/oauth-ruby/releases/tag/v0.5.0) of the oauth gem (see commit [here](https://github.com/ruby-oauth/oauth/pull/106/files)) and we are on 1.1.0, the dependency is no longer needed and can now be removed.

### How has this been tested?
The tests pass. I was also able to navigate the app after this change.

You can view, comment on, or merge this pull request online at:

  https://github.com/openstreetmap/openstreetmap-website/pull/6334

-- Commit Summary --

  * Remove file_exists gem

-- File Changes --

    M Gemfile (3)
    M Gemfile.lock (2)

-- Patch Links --

https://github.com/openstreetmap/openstreetmap-website/pull/6334.patch
https://github.com/openstreetmap/openstreetmap-website/pull/6334.diff

-- 
Reply to this email directly or view it on GitHub:
https://github.com/openstreetmap/openstreetmap-website/pull/6334
You are receiving this because you are subscribed to this thread.

Message ID: <openstreetmap/openstreetmap-website/pull/6334 at github.com>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/rails-dev/attachments/20250818/1f64453c/attachment.htm>