Fix font size for feedback button due to changes to base font-size change

[powellkerry]

Summary

The base font-size specified in the @department-of-veterans-affairs/formation package will be changed from 10px to 16px. This change updates the font-size of the feedback button to adjust to that change

This change will be merged with the other PRs in the related issue.

Related issue(s)

department-of-veterans-affairs/vets-design-system-documentation#2681

Testing done

Local testing and verification, testing will also be done in a review instance

Screenshots

Note: This field is mandatory for UI changes (non-component work should NOT have screenshots).

	Before	After
Desktop

What areas of the site does it impact?

Feedback button

Acceptance criteria

Quality Assurance & Testing

• [x ] I fixed|updated|added unit tests and integration tests for each feature (if applicable).
• [ x] No sensitive information (i.e. PII/credentials/internal URLs/etc.) is captured in logging, hardcoded, or specs
• [x ] Linting warnings have been addressed
• [ x] Documentation has been updated (link to documentation *if necessary)
• [ x] Screenshot of the developed feature is added
• [x ] Accessibility testing has been performed

Error Handling

• [ x] Browser console contains no warnings or errors.
• [x ] Events are being sent to the appropriate logging solution
• [x ] Feature/bug has a monitor built into Datadog or Grafana (if applicable)

Authentication

• [ x] Did you login to a local build and verify all authenticated routes work as expected with a test user

⚠️ Team Sites (only applies to modifications made to the VA.gov header) ⚠️

• [x ] The header does not contain any web-components
• [x ] I used the proxy-rewrite steps to test the injected header scenario
• [x ] I reached out in the #sitewide-public-websites Slack channel for questions

Requested Feedback

(OPTIONAL) What should the reviewers know in addition to the above. Is there anything specific you wish the reviewer to assist with. Do you have any concerns with this PR, why?

[rmessina1010]

LGTM