Replace deprecated mixins with Text component in loading-swaps-quotes

[staging-devin-ai-integration]

Description

This pull request replaces deprecated mixins with the Text component in the loading-swaps-quotes file. The changes include updating the SCSS and JS files to use the Text component and related enums, as well as deleting specific SCSS instances as instructed by the user.

Devin Run Link: https://staging.itsdev.in/devin/edffa827e63141c8a3214c25ecf4a760

Related issues

Partially Fixes: MetaMask#20496

Manual testing steps

1. Go to the latest build of storybook in this PR
2. Manually check if LoadingSwapQuotes is getting rendered properly

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I’ve followed MetaMask Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

Requested by: Shreyasi