Slightly cleaned up cypress tests

[bsekachev]

Motivation and context

1. For us there should not be difference between clearAllCookies and clearCookies as we only use one domain. Thus using clearAllCookies was removed.
2. Minimized using of clearCookies, preferred custom command headlessLogout

How has this been tested?

Checklist

• I submit my changes into the develop branch
• I have created a changelog fragment
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues (see GitHub docs)

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.86%. Comparing base (5a99e73) to head (efe12ce).
Report is 2 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #8975      +/-   ##
===========================================
+ Coverage    73.84%   73.86%   +0.02%     
===========================================
  Files          417      417              
  Lines        44589    44590       +1     
  Branches      4031     4031              
===========================================
+ Hits         32926    32937      +11     
+ Misses       11663    11653      -10     

Components	Coverage Δ
cvat-ui	78.34% <ø> (+0.04%)	⬆️
cvat-server	70.06% <ø> (ø)