Add more calendar theme-aware tokens to provide visual variety of events

[vivinkrishna-ni]

Pull Request

🤨 Rationale

• Refer to the UI mockup for the different variants of work item types used in the SLE UI.
• These tokens can be used to display different event card types in the calendar view, providing distinct visual styling (background color, hover color, border color, and font color) for each type.
• See the calendar color sheet (Requires Emerson access) for the usage of tokens in a tabular format.

👩‍💻 Implementation

• Added additional color tokens for calendar event cards, which will be used primarily to support multiple variants of event cards in the calendar. This token is added based on the provided visual design in different themes.

🧪 Testing

• Verified with the storybook build

✅ Checklist

• I have updated the project documentation to reflect my changes or determined no changes are needed.

[rajsite]

@jattasNI bypassing for token naming which seems well-aligned to naming convention