chore: Create a story for IconButton component

[devin-ai-integration]

Description

Added Storybook stories for the IconButton component to showcase its different states: Default, Disabled, and With Long Label.

Manual testing steps

1. Run yarn storybook to start the Storybook UI.
2. Navigate to the IconButton component under the UI section.
3. Verify that the stories for Default, Disabled, and With Long Label are rendered correctly.

Screenshots/Recordings

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.