Wp-calypso: JPO: do not render field validation in form placeholder.

[AnnaMag]

Steps to reproduce

1. access JPO from an .org site or JP sandbox https://YourJetpackSandbox.com/wp-admin/admin.php?page=jetpack&action=onboard&calypso_env=development to arrive at the first step of the flow
2. whilst the data is being fetched, the form validation displays its required version, which is corrected after the data has been fetched.

What I expected

See a placeholder for the form.

What happened instead

We see redundant (= not updated) validation information.

[tyxla]

Additional thing here: we should probably fix the wording of the validation:

• Required field on error should be changed to something like "Please input your site title"
• Required field on success should be changed to something like "You're all set" (or removed altogether)

[joanrho]

Just chatted with Marin about this and we've decided on:

• Required field on error should be "Please enter a site title" (no icons) with a red border color on the field.
• Required field on success should be removed altogether with a green border color on the field.

[AnnaMag]

Thanks @joanrho and @tyxla- that does seem more relevant. I'll wrangle the changes 👍

[ockham]

Fixed by #22321, #22322, and #22336. Making the same kind of changes to the Business Address step in #22339.