Design updates related to #45143

• Update banner to new styling: https://zpl.io/25vg65W
  - partial green background and slightly adjusted illustration

• remove the 'CLUSTER OVERVIEW' Headline from the overview page (this might be a separate issue, but we don't need this header anymore)

• update email field to 258px wide

• Update email field invalid state to change back to valid once proper email address format is typed

• Update 'X' icon on success toast to match the 'X' icon on the email sign up banner