fix tab handling 1803 and 1787

[smadbe]

Description

Fix tab handling: the problem #1767 fixed by #1787 and also the problem #1787 introduces.

As tab changes is quite complex, especially with tasks, I am not completely sure all cases are ok. Tests I can think of (that I should have test but for which a e2e test might be useful):

• on front page without prior navigation (chapter)
• on task: after loading the first tab is selected
• from first task tab to another
• from a task tab to history
• from history a task tab
• site loaded on the history page url
• site loaded on the history page url, then switch to the content tab which loaded custom tabs
• task tabs appearing/disappearing on resize: check task selection is consistent
• leaving the form with changes: tested through the existing e2e

[smadbe]

[auto-generated message] E2E test report on: https://algorea-static.s3.eu-central-1.amazonaws.com/branch/fix-item-tabs/playwright-report/index.html