Row config view: Fix fallback texts

[BatJan]

Prerequisites

• I have added steps to test this contribution in the description below

Description

I noticed a few fallback texts were missing in this view. I also added a new text to the translation files since it was hardcoded into the view.

Furthermore I added some sr-only texts for some of the buttons in order to improve accessibility.

[umbrabot]

Hi there @BatJan, thank you for this contribution! 👍

While we wait for one of the Core Collaborators team to have a look at your work, we wanted to let you know about that we have a checklist for some of the things we will consider during review:

• It's clear what problem this is solving, there's a connected issue or a description of what the changes do and how to test them
• The automated tests all pass (see "Checks" tab on this PR)
• The level of security for this contribution is the same or improved
• The level of performance for this contribution is the same or improved
• Avoids creating breaking changes; note that behavioral changes might also be perceived as breaking
• If this is a new feature, Umbraco HQ provided guidance on the implementation beforehand
• The contribution looks original and the contributor is presumably allowed to share it

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