[Behat] Fixed System info tests

[mnocon]

Failing build: https://github.com/ibexa/admin-ui/actions/runs/1582117472

    Then I see "Composer" system information table    # Ibexa\AdminUi\Behat\BrowserContext\SystemInfoContext::iSeeSystemInformationTable()
      Failed asserting that expected string 'Composer' is equal to actual 'Packages' for css locator 'tableTitle': '.tab-pane.active .ez-fieldgroup__name'
      Failed asserting that two strings are equal.
      --- Expected
      +++ Actual
      @@ @@
      -'Composer'
      +'Packages'

     Then I see "Symfony Kernel" system information table    # Ibexa\AdminUi\Behat\BrowserContext\SystemInfoContext::iSeeSystemInformationTable()
      Failed asserting that expected string 'Symfony Kernel' is equal to actual 'Bundles' for css locator 'tableTitle': '.tab-pane.active .ez-fieldgroup__name'
      Failed asserting that two strings are equal.
      --- Expected
      +++ Actual
      @@ @@
      -'Symfony Kernel'
      +'Bundles'

Adapting tests to the changes done in #112

I've also decided to use the opportunity and add a quick test for ibexa/system-info#4

[micszo]

Thanks!