Trashed page retains live slug on site using Workflow

## To Reproduce

Step by step instructions to reproduce the behavior:

> 1. Create a Page and add some content to it
> 2. Commit the page to live
> 3. Trash the page
> 4. Create a new page with the same name and add content to it
> 5. Commit the page to live.
> 6. Try to visit the new page using the same old slug

## Expected behavior
> I expected the trashed page to release the live slug/commit the new trashed slug so that the live slug could be reused.

## Describe the bug
> We have a site using Workflow for localization. When a page is trashed the `Draft` slug is updated to a trashed one, but the Live slug on the page remains attached to the trashed page. When we try to create a new page with the same name the new page uses the real slug on its `Draft` but the `Live` versions add a number at the end of the Slug. In order to solve this issue I have to go to the trashed page and `Commit` the new trash slug and liberate the live one.

## Details

**Node.js:**
v12.14.1

**ApostropheCMS:**
v2.114.0

**Server Operating System:**
I can reproduce the error on my local environment. MacOS Big Sur v11.1

Start by reproducing the workflow in a local ApostropheCMS v2.114.0 site using the listed page, trash, replacement, and live-commit steps. Trace how Draft and Live slugs change when a page is trashed and when the replacement is committed; done means the trashed page releases the live slug and the replacement can use it without a numeric suffix.

Written by the indexing model from the issue text.