Add tests for the module functionality on contact forms

There should be tests for:

• Verifying the contact forms with and without permissions (existence and number of file fields).
• Verifying the form validation handler with and without settings set for different roles.
• Verifying that the settings for a specific user role always overrides the settings for the authenticated user role.
• Verifying that the highest number of allowed attachments is used when the user has more than one permitted role with settings set.
• Verifying that the highest maximum upload size is used when the user has more than one permitted role with settings set.
• Verifying that allowed extensions are aggregated across all of the user's valid roles with settings set.
• Verifying that it is possible to send mail with attachments when passing the validation.
• Verifying that the sent mail contains the attachment(s).