Remove specific tag from unit test

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 86.40%. Comparing base (0cf7111) to head (b1c7dcf). Report is 8 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #259 +/- ## ========================================== - Coverage 86.44% 86.40% -0.04% ========================================== Files 18 18 Lines 2567 2567 ========================================== - Hits 2219 2218 -1 - Misses 348 349 +1 ``` | [Flag](https://app.codecov.io/gh/RedHatQE/widgetastic.core/pull/259/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=RedHatQE) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/RedHatQE/widgetastic.core/pull/259/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=RedHatQE) | `86.40% <ø> (-0.04%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=RedHatQE#carryforward-flags-in-the-pull-request-comment) to find out more.

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