Change toolbar's permission label to 'Use the toolbar'

Problem/Motivation

Splitting this off from #1044090-6: Enable toolbar for authenticated users also, so that non-admin users can use shortcuts as well point 2.

The toolbar doesn't have to be just for "administration". Especially once #2135445: Toolbar displays Manage tab even if the user is not permitted to see it is fixed, toolbar is very useful for content editors or even regular authenticated users, as a slick/easy way to access shortcuts, to have a nicer user menu experience, and potentially other links/trays added via contrib.

However, while the machine name for the permission to use the toolbar is access toolbar, the human-readable label in the admin UI is unfortunately called "Use the administration toolbar". This implies the toolbar is for "administration", and that granting this permission to non-admins is a bad idea. This is not true (or at least, won't be true once #2135445 is committed).

Proposed resolution

Rename the label to just "Use the toolbar".

Machine name of the permission (access toolbar) remains unchanged. Therefore, no impact on existing installs, no upgrade path required, etc.

The only impact is a minor translation break for this permission label. Should be an easy fix for translators, since they only have to remove something from the existing translations.

Remaining tasks

1. Upload the trivial patch.
2. Get sign-off from the appropriate folks (usability team? anyone else?)
3. Decide if we need a change record, and if so, write it. Draft text in the Release notes section below
4. Commit

User interface changes

A small change to the human-readable label for toolbar's one and only permission, to remove the unnecessary word "administration".

API changes

None.

Data model changes

None. The machine name for the permission is unchanged. No impact on existing or future installs.

Release notes snippet

The permission to use the toolbar has been renamed from "Use the administration toolbar" to "Use the toolbar". The toolbar does not require a user have permissions to perform any "administration" tasks, so the permission label has been simplified to make it clear to site builders that the toolbar could be enabled for various non-administrator roles. The machine name for this permission (access toolbar) remains as-is, so no changes are required to existing site configurations.