Update initial password setup page

Problem to solve

While discussing this page with @ljlane, we noticed that the alert message and the form title look different.

#215714 (comment 358191391)

• It's the initial password setup, so the change the password title on the UI made me think.

Proposal

• Update the wording on the UI text to set up new password
• Design: https://www.figma.com/file/1rMJcVJqo8spfy88lTzOcT/221041-Set-initial-password?node-id=2%3A70