Refine UX for registering with missing name

Context

On the registration page, errors are displayed in the old style. They should be displayed in the new style of in an input validation.

Current behavior	Correct behavior
Validation errors are shown on the top of the page	Validation errors are displayed as part of the form element

Error copy

• First name = First name is required.
• Last name = Last name is required.
• Username = Username is taken.
• Username = Username is required.
• Email = Email is taken.
• Email = Email is required.
• Email = Enter a valid email address.
• Password = Password must be at least 8 characters.
• Password = Password is required.

Conversations from MR

cc @luzhiyuan.deer

From @katiemacoy:

Could you update the error messaging to have form validation? You can read more in our documentation.

We will probably want to change the copy as well. Perhaps Last name is required.

We should also make sure other form elements on this page use the same form validation and have similar copy. Let me know what you think.

The following discussion from !105013 (merged) should be addressed:

• @katiemacoy started a discussion: (+5 comments)

  hey @luzhiyuan.deer @cablett @hmehra I'm happy to do the UX review on this one but I'm a bit unclear what I should be checking for. Should I try to save the registration from with the last name missing?