[BUGFIX] EM: configuration view CSS corrections

Corrects padding+margins for text, group, container in
configureExtension view.

Change-Id: If6ea1f596e13ae1179e01ad3798e900f64ce8dd2
Fixes: #46958
Releases: 6.1, 6.0
Reviewed-on: https://review.typo3.org/19661
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn