fix(VSelect): change onMouseUp to handle menu toggle on mouse events

[webstp]

Description

When append-inner was clicked, the menu could be opened but not closed, this was cause by onClick
always setting the isMenuActive to true. Made a change to only allow onMouseUp totoggle isMenuActive
state when the append-inner icon is clicked

Motivation and Context

fix #6564

How Has This Been Tested?

I create tests for the bug and ran the unit tests

Markup:

<template>
  <v-autocomplete  :items="states"></v-autocomplete>
</template>

<script>
export default {
  data () {
    return {
      states: [
          'Alabama', 'Alaska', 'American Samoa', 'Arizona',
          'Arkansas', 'California', 'Colorado', 'Connecticut',
          'Delaware', 'District of Columbia', 'Federated States of Micronesia',
          'Florida', 'Georgia', 'Guam', 'Hawaii', 'Idaho',
          'Illinois', 'Indiana', 'Iowa', 'Kansas', 'Kentucky',
          'Louisiana', 'Maine', 'Marshall Islands', 'Maryland',
          'Massachusetts', 'Michigan', 'Minnesota', 'Mississippi',
          'Missouri', 'Montana', 'Nebraska', 'Nevada',
          'New Hampshire', 'New Jersey', 'New Mexico', 'New York',
          'North Carolina', 'North Dakota', 'Northern Mariana Islands', 'Ohio',
          'Oklahoma', 'Oregon', 'Palau', 'Pennsylvania', 'Puerto Rico',
          'Rhode Island', 'South Carolina', 'South Dakota', 'Tennessee',
          'Texas', 'Utah', 'Vermont', 'Virgin Island', 'Virginia',
          'Washington', 'West Virginia', 'Wisconsin', 'Wyoming',
        ]
    }
  }
}
</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 breaking 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)
• I've added new examples to the kitchen (applies to new features and breaking changes in core library)

[nekosaur]

Please add Playground markup that shows the issue

[webstp]

Updated with Markup

[johnleider]

I'd like to get this in for v2.2. If you don't have time let me know.

[johnleider]

Requesting final comments @vuetifyjs/core-contributors @vuetifyjs/core-team