[Optimization] Optimize DOM in tempo.js

[AnvitaPrasad]

Issue: #4461

DOM Optimization in tempo.js widget

Optimized the tempo.js widget to improve performance by:

1. Caching canvas contexts during initialization instead of getting them repeatedly in the draw loop
2. Creating a style template object for efficient application to multiple canvases
3. Caching frequently accessed properties (blockList, logo) to reduce property lookups
4. Simplifying conditional logic using ternary operators for cleaner, faster code
5. Reusing current time values instead of creating multiple Date objects
6. Extracting canvas click handler to a separate method for better organization

These changes maintain identical functionality while improving rendering efficiency, especially during animation loops that run at 5ms intervals.

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[AnvitaPrasad]

@walterbender pls review . thanks

[github-actions]

This pull request has been open for more than 60 days without any activity. It will be closed in 3 days unless the stale label is removed or commented on.

[github-actions]

Closed pull request due to inactivity for more than 63 days.

[walterbender]

This needs to be a separate call to getTime()

[walterbender]

How did you test this? To me, the changes to getTime don't look correct.

[github-actions]

Closed pull request due to inactivity for more than 63 days.