fix(tests): cleanup test code

[ludmilanesvitiy]

PR Checklist

Before creating new PR, please take a look at checklist below to make sure that you've done everything that needs to be done before we can merge it.

• read and followed the CONTRIBUTING.md guide.
• built and tested the changes locally.
• added/updated tests.
• added/updated API documentation.
• added/updated demos.

[codecov]

Codecov Report

Merging #4778 into development will increase coverage by 0.02%.
The diff coverage is n/a.

@@               Coverage Diff               @@
##           development    #4778      +/-   ##
===============================================
+ Coverage        74.31%   74.34%   +0.02%     
===============================================
  Files              202      202              
  Lines             7102     7102              
  Branches          1447     1447              
===============================================
+ Hits              5278     5280       +2     
+ Misses            1429     1425       -4     
- Partials           395      397       +2

Impacted Files	Coverage Δ
src/typeahead/typeahead.directive.ts	72.77% <0%> (+1.04%)	⬆️

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