fix(ComboBox): avoid extra onSelectionChange calls

[reidbarber]

Closes #9727

Before:

• Selecting an option fired onSelectionChange once (expected)
• Clicking away fired it one extra time
• Tabbing away fired it two extra times

After:

• No extra onSelectionChange calls occur when values are already in sync

✅ 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:

Unit tests should cover, but smoke test in storybook.

🧢 Your Project:

[rspbot]

Build successful! 🎉

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

[LFDanLu]

doing some testing still, but do you know if this was a regression? Feels like didn't use to happen...

EDIT: has been happening since last Feb at least, so probably not a regression

[snowystinger]

is this still true if it allows a custom value?

[LFDanLu]

I think useComboBoxState will still clear the selected key on field blur via

react-spectrum/packages/@react-stately/combobox/src/useComboBoxState.ts

Line 422 in a6e720d

commitValue();

still