It was added because of cockpit-starter-kit[1] but they already dropped
it[2] because

> starter-kit does not use it directly, and none of our derived projects
> have it.

Thus, in principle it does not make sense to keep it as Agama
dependency.

As weird side-effect, a few test were fixed to "waitFor" the expeced
content.

[1] 55c75c3
[2] cockpit-project/starter-kit@67c1c06

It[1] was added more than a year ago[2] in the context of "Adapt React
components to the Starter Kit". But probably is no longer needed since
async functions, ES6 generators, and `yield` JavaScript operator have
broad support among major browsers.

[1] https://github.com/facebook/regenerator
[2] 55c75c3

It was there because cockpit-starter-kit, which dropped it a year
ago[1][2]

[1] cockpit-project/starter-kit#590
[2] cockpit-project/starter-kit@6e1fd84

Which came from cockpit-starter-kit. It was dropped there few months
ago, in Jun 2023[1]

[1] cockpit-project/starter-kit@1e46595

For waiting for the expected content

Remove a leftover it.only and make examples wait a bit for the expected
content.

For waiting a bit to find the expected content