Update the New User Registration Trial /company Page

What does this MR do and why?

Related to #527168

1. Update the style of company page
2. Remove website field
3. Conditionally show the name fields
4. Change the phone pattern help text to only show as a validation error message.

References

Screenshots or screen recordings

	Trial start from /-/trial_registrations/new	Trial mid registration
Before
After
With phone number validation error
With name fields

How to set up and validate locally

1. Setup gdk to simulate saas: https://docs.gitlab.com/development/ee_features/#simulate-a-saas-instance
2. For first case, go to /-/trial_registrations/new, complete sign up form and welcome page, you should see the company form page.
3. For second case, go to /users/sign_up, complete sign up form, and on welcome page, select Create a new project and My company or team, you should land on the company form after.

MR acceptance checklist

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