Update design for browser Settings to use new design style

[aguscruiz]

Description

We have a new design ready for the browser settings pages to modernize using Nala styles.

Disclaimer: The actual content in each page may be outdated in terms of reflecting the content they should have. Use this design only as a reference for the design styles

https://www.figma.com/file/IXNCYwXmMWaF6u7Pdv1pOW/Desktop-settings---Nala?type=design&node-id=214-26840&mode=design

Actual result:

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Expected result:

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Reproduces how often:

Brave version (brave://version info)

Version/Channel Information:

• Can you reproduce this issue with the current release?
• Can you reproduce this issue with the beta channel?
• Can you reproduce this issue with the nightly channel?

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields?
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Miscellaneous Information:

[NayamAmarshe]

The top-bar colors look quite in contrast. It should be updated to reflect a more colder color. This dynamic of fiery top bar with soothing indigo buttons looks odd.