Require src/store/middlewares to have 100% test line coverage

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Expected behaviour

Middlewares and reducers are the core of our application, so they should have the best test coverage. It is usually quite easy to test them.
karma-coverage check should be set up to override test coverage to require 100% line coverage on src/store/**, so that when we are adding more middlewares and reducers, CI will not allow us to merge it without full test coverage.

Actual behaviour

Some parts are missing test coverage.