Update to DS@3.4.8 and update buttons and pagination, etc

[anselmbradford]

Changes

• Update buttons and pagination to use new flex-based layouts and remove button icon-related class names.
• Use u-small-text--subtle from the DS.
• Migrate attach to behaviorAttach.

How to test this PR

1. Check prepaid products agreements db and check that the pagination looks fine.
2. Check the disclosures tool and see that the button group for navigating steps has the buttons properly spaced apart and that the step 2 loading icon is on the right.
3. Check the gradpath tool and see that the navigation buttons have centered text and are unchanged to prod.
4. Check the Before You Claim tool and enter dob and income amounts and see that the loading icon on the submit button works.
5. Check http://localhost:8000/privacy/disclosure-consent/ and http://localhost:8000/privacy/records-access/ form and edit the submit button (or submit test data) to see that loading icon appears when the a-btn--hide-icon class is removed.
6. Check video close button after playing a video, such as http://localhost:8000/about-us/blog/addressing-racial-inequities-consumer-finance-markets/
7. Check </> buttons on http://localhost:8000/owning-a-home/loan-estimate/

Screenshots

Before:

After:

[paulhyland]

@anselmbradford - checked all the file updates and none of them affect our GTM triggers. For buttons, we only look for the classes a-btn and btn (the latter used by Mosaic).

So I approve from my end, but since I don't know if one of the other reviewers needs to run the tests under "How to test this PR", I'm not approving/triggering the merge.

[anselmbradford]

Reviewers, the SonarCloud failure is for the heavy amount of duplication between https://www.consumerfinance.gov/privacy/disclosure-consent/ and https://www.consumerfinance.gov/privacy/records-access/, which predates this PR.

[wpears]

The video button looks weird to me, see:

Seems like the icon should be to the right of the vertical line or the vertical line should not exist.

[anselmbradford]

The video button looks weird to me, see:

Fixed!

[anselmbradford]

FYI I force pushed

[wpears]

🆒