fix(VTimePicker): AM/PM farsi translation and margins in RTL mode

[jacekkarczmarczyk]

Motivation and Context

Fixes few issues from #6757:

• margins of am/pm in title
• Farsi translations of am/pm
• typing of VTimePickerTItle.format prop

How Has This Been Tested?

playground

Markup:

<template>
  <v-container fluid style="width: 314px">
    <v-btn block @click="$vuetify.rtl = !$vuetify.rtl">RTL: {{ $vuetify.rtl }}</v-btn>
    <v-time-picker />
    <v-time-picker format="24hr" />
    <v-time-picker ampm-in-title />
    <v-time-picker format="24hr" ampm-in-title />
  </v-container>
</template>

<script>
  import Vue from 'vue';
  import { fa } from '../src/locale'
  export default Vue.extend({
    created () {
      this.$vuetify.lang.locales.en = fa
    }
  })
</script>

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement/refactoring (non-breaking change that doesn't add any features but makes things better)

Checklist:

• The PR title is no longer than 64 characters.
• The PR is submitted to the correct branch (master for bug fixes and documentation updates, dev for new features and backwards compatible changes and next for non-backwards compatible changes).
• My code follows the code style of this project.
• I've added relevant changes to the documentation (applies to new features and breaking changes in core library)