[a11y] 11.1.3.1a Info and relationships (headings)

[tschiebel]

audit: https://infinite.owncloud.com/s/qSvYucPltEYUhhc

https://github.com/BIK-BITV/BIK-App-Test/tree/main/Pr%C3%BCfschritte/de
https://www.etsi.org/deliver/etsi_en/301500_301599/301549/03.02.01_60/en_301549v030201p.pdf

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• The visually clearly recognizable headings "Pending", "Accepted" and "Rejected"
  are not marked as such.

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• The visual labels of the input fields were incorrectly converted to headings.
  as headings. In order to avoid duplicate output of the labels, it is
  it is advisable to hide the visual labels for screen reader users. The labels should only be displayed
  when the corresponding field is focused with the screen reader.