ui5-datepicker: error valueState would be displayed if date picker with maxDate and minDate defined has an empty value

[zhangliangyi]

Hi Colleagues,

I am from Experience Web team in SAP Successfactors.

The issue is that the datepicker with minDate and maxDate would set the valueState to Error once the date value is changed to empty value.

Steps to reproduce the behavior:

1. Go to https://sap.github.io/ui5-webcomponents/playground/components/DatePicker/
2. Select a date in the date picker component in section DatePicker with Minimum and Maximum Date - 1/1/2020 - 4/5/2020 format-pattern="dd/MM/yyyy"
3. Remove the value in the picker

Expected behavior
The date picker should not have the error valueState unless it is required.

Screenshots

Context

• UI5 Web Components version: rc7
• OS/Platform: MacOS
• Browser (if relevant): Chrome
• Other information: N/A