Prop with required: false or default value should not trigger prop validation error when not provided

[octref]

From #2135 (comment)

[octref]

• Use DiagnosticSeverity.Error for passing an undeclared prop
• When not passing a required prop
  • If in array form, show a warning with DiagnosticSeverity.Warning (as all props are optional)
  • If in object form, only show error if required props are not passed. For example, if a component requires foo and takes an optional bar, not passing bar should not generate an error.

[yoyo930021]

When no component prop in template:

// case 1 -> warning
props: [foo, bar]
// case 2 -> warning
props: {
  foo: String,
  bar: String,
}
// case 3 -> error
props: {
  foo: {
    type: String,
    required: true
  }
}
// case 4 -> No any errors or warning
props: {
  foo: {
    type: String,
    required: false
  },
  bar: {
    type: String,
    default: ''
  }
}