feat(VDatePicker): add events and event-color support for date picker

[maryamBaratii]

Description

• Restores the events and event-color props in VDatePicker for month view.
• Allows event markers to be displayed on months, similar to the behavior in Vuetify 2.
• Ensures the correct color is applied to event markers.
• Updated documentation to reflect the new props.

Fixes #19296

Markup:

<template>
  <v-app>
    <v-container>
      <v-date-picker
        :event-color="date => date[9] % 2 ? 'red' : 'yellow'"
        :events="functionEvents"
        :v-model="date2"
      />
    </v-container>
  </v-app>
</template>

<script setup>
  import { onMounted, ref } from 'vue'

  const arrayEvents = ref(null)
  const date2 = ref((new Date(Date.now() - (new Date()).getTimezoneOffset() * 60000)).toISOString().substr(0, 10))
  function functionEvents (date) {
    const [, , day] = date.split('-')
    if ([12, 17, 28].includes(parseInt(day, 10))) return true
    if ([1, 19, 22].includes(parseInt(day, 10))) return ['red', '#00f']
    return false
  }
  onMounted(() => {
    arrayEvents.value = [...Array(6)].map(() => {
      const day = Math.floor(Math.random() * 30)
      const d = new Date()
      d.setDate(day)
      return d.toISOString().substr(0, 10)
    })
  })
</script>