Updates to visibility toggle in Form fields for Web

[janogarcia]

The following changes only apply to the medium size of the Button component on Web.

Figma — Form component

• [ ] Changed: The visibility toggle buttons for Password fields are now 28x28 (following the specs for SM icon buttons) and the nested icon is 20px instead of 24px.
• [ ] Changed: The right/end padding for the Password field is now 12px instead of 8px.