Description:

As removing users is an action that can't be undone, it's more secure to ask for a password confirmation in the UI.
This will prevent accidentally removing users and will make it e.g. impossible to use an active session of someone else to remove users without knowing his password.

Note: This PR also improves the error handling of bulk requests in AjaxHandler. When e.g. removing multiple users, this is done in a bulk request. If an error occurs (like incorrect password), an error notification was previously created containing each error response of the bulk request. This could e.g. cause that the incorrect password error was show hundreds of times in the error notification. With the changes in this PR, the error messages will be counted and only printed once (together with the count).

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