Operation 'add terms' on vocabulary list should respect the access policy

Problem/Motivation

On the vocabularies page (/admin/structure/taxonomy) the "add terms" operation is present without checking if the current used is able to add terms.

True, by default, if you are on that page you have administer taxonomy permissions. The same permissions are needed to add terms (off-topic: this is bad!). But in the case a contrib module implements different access check for adding terms, this needs to be verified before adding the link in operations.

Proposed resolution

Fix it.

Remaining tasks

None.

User interface changes

None.

API changes

None.

Data model changes

None.