spoofed_media_type error when the file name is broken

[sobrinho]

Describe the bug
Using a file named original. breaks the spoof validation.

To Reproduce
Attach a file on a URL that returns the content type header as image/png but the file name is broken such as original..

Expected behavior
Ignore the spoof validation against file extension.

Screenshots
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Desktop (please complete the following information):
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Smartphone (please complete the following information):
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Additional context
Probably broken because of:

File.extname("original.")
#=> "."

[sobrinho]

Our monkey patch so far:

Paperclip::MediaTypeSpoofDetector.class_eval do
  def has_extension?
    filename_extension.present?
  end
end

Trying to validate if that's okay.