Revert "[BUGFIX] Fix wrong column title in web>list for field colpos"

This reverts commit 7a1aaf727d04f56252ca173a59489d2f77f9655a

The patch triggers warnings and errors in multiple extensions. Digging
into the details shows the implementation is neither finished nor
stable. See issue #25113 for a detailed analysis.

Change-Id: I07153613ecc062ecc777a45962f11d0b37cf8730
Related: #25113
Fixes: #45833
Releases: 6.1, 6.0, 4.7, 4.6, 4.5
Reviewed-on: https://review.typo3.org/18943
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn