[ISSUE-5815] Add font size extension

[kart-c]

Changes Overview

Add new font size extension. Add the relative demos and test cases for the same.

Implementation Approach

Followed the similar code structure as the other extensions.

Testing Done

Added demos for React and Vue. Added test cases for both examples.

Verification Steps

Netlify preview links
React
Vue

Checklist

• I have created a changeset for this PR if necessary.
• My changes do not break the library.
• I have added tests where applicable.
• I have followed the project guidelines.
• I have fixed any lint issues.

Related Issues

#5815

[changeset-bot]

⚠️ No Changeset found

Latest commit: 19891d0

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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[nperez0111]

This is fantastic @kart-c I appreciate your contribution