[useDatePickerState]: Cannot use 'in' operator to search for 'timeZone' in null

[artaommahe]

🐛 Bug Report

• open an example fora date picker https://codesandbox.io/s/white-breeze-rer8g2?file=/src/DatePicker.js
• open first date picker
• select a hour segment
• clear it (press backspace 2 times)
• see an error Cannot use 'in' operator to search for 'timeZone' in null

Also type for DatePickerState.timeValue is wrong - field can be null, but the type is DatePickerState.timeValue: TimeValue. Same with DateRangePickerState.timeRange.

🤔 Expected Behavior

no error and proper type of the field DatePickerState.timeValue: TimeValue | null

😯 Current Behavior

TypeError
Cannot use 'in' operator to search for 'timeZone' in null
    at commitValue (https://rer8g2.csb.app/node_modules/
react-stately/datepicker/dist/module.js:122:26

💁 Possible Solution

🔦 Context

💻 Code Sample

🌍 Your Environment

Software	Version(s)
react-spectrum	3.21.0/3.25.0
Browser	Chrome
Operating System	MacOS

🧢 Your Company/Team

🕷 Tracking Issue (optional)

[LFDanLu]

Reproduced in the Spectrum DatePicker as well. Looks like the TimeField onChange is calling selectTime with null, resulting the observed break here. Will have to handle the null case in that line but also make sure not to clear the timezone in the TimePicker