Epics won't show Issues toolbar once license renewal notification is triggered

Summary

Once license renewal notification is triggered, Epics page won't show Issues toolbar so that linked issues are not listed and new issues cannot be created directly under it.

Steps to reproduce

• Apply a Premium license with less than 14 days of validity.
• Head over to a Group, create an Epic and click on it.
• You will find the Issues toolbar missing below the Issues title.

What is the current bug behavior?

• Epics page won't show Issues toolbar once license renewal notification is triggered.

What is the expected correct behavior?

• Epics page should show Issues toolbar in any case (in line with what the license permits).

Relevant logs and/or screenshots

Screenshot:

This is the error on browser console:

epic_tabs.js:10 Uncaught TypeError: Cannot read property 'querySelector' of null
    at new e (epic_tabs.js:10)
    at HTMLDocument.<anonymous> (index.js:11)

Results of GitLab environment info

root@12106-ee:~# gitlab-rake gitlab:env:info

System information
System:		Ubuntu 16.04
Proxy:		no
Current User:	git
Using RVM:	no
Ruby Version:	2.6.5p114
Gem Version:	2.7.10
Bundler Version:1.17.3
Rake Version:	12.3.3
Redis Version:	5.0.7
Git Version:	2.26.2
Sidekiq Version:5.2.7
Go Version:	unknown

GitLab information
Version:	12.10.6-ee
Revision:	933c215f042
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	PostgreSQL
DB Version:	11.7
URL:		http://12106-ee
HTTP Clone URL:	http://12106-ee/some-group/some-project.git
SSH Clone URL:	git@12106-ee:some-group/some-project.git
Elasticsearch:	no
Geo:		no
Using LDAP:	no
Using Omniauth:	yes
Omniauth Providers:

GitLab Shell
Version:	12.2.0
Repository storage paths:
- default: 	/var/opt/gitlab/git-data/repositories
GitLab Shell path:		/opt/gitlab/embedded/service/gitlab-shell
Git:		/opt/gitlab/embedded/bin/git

Results of GitLab application Check

root@12106-ee:~# gitlab-rake gitlab:check SANITIZE=true
Checking GitLab subtasks ...

Checking GitLab Shell ...

GitLab Shell: ... GitLab Shell version >= 12.2.0 ? ... OK (12.2.0)
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Internal API available: OK
Redis available via internal API: OK
gitlab-shell self-check successful

Checking GitLab Shell ... Finished

Checking Gitaly ...

Gitaly: ... default ... OK

Checking Gitaly ... Finished

Checking Sidekiq ...

Sidekiq: ... Running? ... yes
Number of Sidekiq processes ... 1

Checking Sidekiq ... Finished

Checking Incoming Email ...

Incoming Email: ... Reply by email is disabled in config/gitlab.yml

Checking Incoming Email ... Finished

Checking LDAP ...

LDAP: ... LDAP is disabled in config/gitlab.yml

Checking LDAP ... Finished

Checking GitLab App ...

Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... skipped (no tmp uploads folder yet)
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
3/1 ... yes
4/2 ... yes
3/3 ... yes
Redis version >= 4.0.0? ... yes
Ruby version >= 2.5.3 ? ... yes (2.6.5)
Git version >= 2.22.0 ? ... yes (2.26.2)
Git user has default SSH configuration? ... yes
Active users: ... 2
Is authorized keys file accessible? ... yes
Elasticsearch version 5.6 - 6.x? ... skipped (elasticsearch is disabled)

Checking GitLab App ... Finished


Checking GitLab subtasks ... Finished