fix(S2): adjust Menu/Picker/ComboBox item transition to prevent background color transition

[reidbarber]

Adjusts the S2 Menu, Picker, and ComboBox item styles to where the default transition (containing 150ms duration) does not apply to the background color, but still applies to transform (for press scaling).

From a UX perspective, this was making these components feel laggy/unresponsive when moving the cursor between items quickly. Open to feedback for this, just wanted to get up a PR for people to try out.

Before	After
before-removing-transitions.mov	after-removing-transitions.mov

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

On an S2 Menu, Picker, or ComboBox and move your cursor quickly between items. Observe the behavior difference between production (it should feel snappier now).

🧢 Your Project:

[rspbot]

Build successful! 🎉

• View the storybook
• View the S2 storybook
• View the S2 docs
• View the React Aria docs

[snowystinger]

This feels much better

[yihuiliao]

i agree that it does feel better, but wondering how we landed on this transition to begin with and if it was a specific spec from Spectrum

[reidbarber]

wondering how we landed on this transition to begin with and if it was a specific spec from Spectrum

I couldn't find any definitions anywhere. I think we may have used defaults that we had in S1.