Branch permissions don't prevent tag creation

Issue Summary

Assume that you have a private repo, and a User Group named 'Developers' that has Write access to the repo.

If you create a branch permission for e.g. master branch on this repo, with Write access: None, users of the 'Developers' User Group will still be able to push tags on master or create a tag on a commit of master from UI.

Steps to Reproduce

1. Create a private Bitbucket repo
2. Push some commits to the repo
3. Create a User Group named 'Developers' in the workspace that owns the repo, and add some users
4. Grant to this User Group Write access to the repo
5. Create a branch permission in this repo for master branch, with Write access: None
6. One of the users that belongs to the 'Developers' user group tries to create a tag on a commit of master from Bitbucket UI, OR
   tries to push a tag in a commit of master

Expected Results

The user is prevented from creating a tag via the UI and from pushing a tag on master

Actual Results

The user can create a tag in a commit of master from the UI and can also push a tag on master

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available