Align triggering validation on property changes

[vursen]

Motivation

Validation is not triggered consistently on constraint and value property changes across field components. To illustrate the issue, look at how different components handle validation on change of different properties:

TimePicker

Property	Validation on change
value	no
min	no
max	no
pattern	only if already invalid and pattern is defined
required	no

DatePicker

Property	Validation on change
value	only if value is provided
min	only if value is provided
max	only if value is provided
pattern	only if already invalid and pattern is defined
required	no

Select

Property	Validation on change
value	always
required	no

NumberField

Property	Validation on change
value	only if already invalid
step	only if already invalid and step is defined
min	only if already invalid and min is defined
max	only if already invalid and max is defined
required	only if already invalid and required is defined (= true)

So, as you can see, things are quite inconsistent at the moment. One of the reasons is that not all the components are currently using InputConstraintsMixin.

Proposal

• Validate on value property change when at least one constraint is defined.
• Validate on constraint property change when a non-empty value is provided (extracted to #4371).

Also, prefer using InputConstraintsMixin wherever possible.

Components

• TextField
• EmailField
• PasswordField
• Select
• ComboBox / MultiSelectComboBox
• DatePicker
• TimePicker
• DateTimePicker
• IntegerField
• NumberField
• CheckboxGroup
• RadioGroup
• TextArea

[vursen]

Related to #4170 in terms of both affecting the validation logic in InputConstraintsMixin.

[vursen]

A similar issue for Flow components: vaadin/flow-components#2370