[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

Shared with me

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

-> Fixed in #1450

Add account

• [ ] 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. ( -> the Add Account wizard was replaced in the meantime: [feature/account-wizard] Add account wizard #1274 )