va-need-help: align header font-size with Figma

[jamigibbs]

Chromatic

https://3655-need-help-header--65a6e2ed2314f7b8f98609d8.chromatic.com

Description

Figma is showing the header font size as 20px/1.25rem so this will update it to use the corresponding header token. There is a slight decrease in font size which is expected.

Closes department-of-veterans-affairs/vets-design-system-documentation#3655

QA Checklist

• Component maintains 1:1 parity with design mocks
• Text is consistent with what's been provided in the mocks
• Component behaves as expected across breakpoints
• Accessibility expert has signed off on code changes (if applicable. If not applicable provide reason why)
• Designer has signed off on changes (if applicable. If not applicable provide reason why)
• Tab order and focus state work as expected
• Changes have been tested against screen readers (if applicable. If not applicable provide reason why)
• New components are covered by e2e tests; updates to existing components are covered by existing test suite
• Changes have been tested in vets-website using Verdaccio (if applicable. If not applicable provide reason why)

Screenshots

before

after

Acceptance criteria

• QA checklist has been completed
• Screenshots have been attached that cover desktop and mobile screens

Definition of done

• Documentation has been updated, if applicable
• A link has been provided to the originating GitHub issue