Fix state leaking across specs

What does this MR do and why?

Issue is being updated in the previous test example and should have been rolled back, but for some reason the Action Cable process in the next test still sees the issue as confidential

To reproduce the failure, just run:

bundle exec rspec './spec/features/projects/issues/email_participants_spec.rb'

This is also related to the upgrade of vue-apollo because in 3.1.0, failed subscriptions now get retried. The retrying behavior causes our spec teardown to not work properly so the spec fails.

Previously, the spec still passes even with the failed subscription because the test isn't related to the subscription.

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