- Call `visible_to_user?` when counting events
- Caching `visible_to_user?` to reduce the number of queries
- Add ee factory for events to create valid group event

Adds frozen string to the following:

* spec/bin/**/*.rb
* spec/config/**/*.rb
* spec/controllers/**/*.rb

xref https://gitlab.com/gitlab-org/gitlab-ce/issues/59758

This fixes the bug, when approver filter is provided,
but dashboard asks to enter any filter

[master] EE Resolve "Personal access token with only `read_user` scope can be used to authenticate any web request"

See merge request gitlab/gitlab-ee!726

[master] Resolve "Personal access token with only `read_user` scope can be used to authenticate any web request"

See merge request gitlab/gitlabhq!2583

When listing issues and merge requests on dasboard page,
make sure that at least one filter is enabled.

User's id is used in search autocomplete widget instead
of username, which allows presetting user in filter dropdowns.

Related to #43246

(cherry picked from commit 37193ac0da0e5e33080d6af6e41d8896854ee37e)

When listing issues and merge requests on dasboard page,
make sure that at least one filter is enabled.

User's id is used in search autocomplete widget instead
of username, which allows presetting user in filter dropdowns.

Related to #43246