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

This reverts commit 765ebd0cd992b86f8002f932bb51b2a39c0ace99

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: I1ff1ea11feb34c71d3ee42789c3deda130aa9a0e
Related: #25113
Fixes: #45833
Releases: 6.1, 6.0, 4.7, 4.6, 4.5
Reviewed-on: https://review.typo3.org/18942
Reviewed-by: Ernesto Baschny
Tested-by: Ernesto Baschny
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn