Add countdown redirection to User Invite error page #20082

Description:

This addition adds a countdown redirection to the User invite error page. If a user clicked on an expired or invalid invite link then they would be redirected back to the login page of the Matomo instance. This helps the user back out of the exception error page.

I've also written the translation of the error in more plain language. This provides a couple of clear reasons which they can attempt to resolve.

An additional change was to remove the Login_InvalidUsernameEmail translation when the acceptInvitation controller couldn't find a user. This response might be a bit confusing as it is really the technical downstream reason for failure and not really actionable by the user.

Review

• [ ] Functional review done
• [ ] Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• [ ] Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• [ ] Security review done
• [ ] Wording review done
• [ ] Code review done
• [ ] Tests were added if useful/possible
• [ ] Reviewed for breaking changes
• [ ] Developer changelog updated if needed
• [ ] Documentation added if needed
• [ ] Existing documentation updated if needed