User email not confirmed before saving on update.

This issue links to [Asp.net core identity change username/email](https://stackoverflow.com/q/54128505/1841839)

## Steps to reproduce:
Create new asp.net core web application (asp.net core 2.2, mvc). Add Identity scaffolding. In Areas/identity/pages/account/manage/Index.cshtml.cs

## Expected behavior:

User changing email should require conformation of the email before actually saving the email.

## Actual behavior:

1. Email confirmation required for login
2. User signs up + confirms email
3. User changes email
4. Change is saved without confirmation

In the event that the user had miss typed their email they will now be locked out of their account