Dropdown menu accessibility

## What should happen?
In Dropdown menu , when press esc key from a dropped down item, focus returns to the first item in the menu bar, not return to the menu item that is the parent of the dropdown.

## What happens instead?
If press escape , returns to the first item of the menu.
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## Possible Solution

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## Test Case and/or Steps to Reproduce (for bugs)

Test Case:

How to reproduce:
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## Context

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## Your Environment

- Foundation version(s) used: 6.7.4
- Browser(s) name and version(s):
- Device, Operating System and version:
- Link to your project:

## Checklist

- [x] I have read and follow the CONTRIBUTING.md document.
- [x] There are no other issues similar to this one.
- [ ] The issue title and template are correctly filled.

No source file or test is named. Start by reproducing the Escape-key behavior in the Foundation 6.7.4 dropdown menu and trace its keyboard focus handling. Done means Escape returns focus to the parent menu item rather than the first menu item.

Written by the indexing model from the issue text.