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

This reverts commit 50eba0a8eee20f9ecc2b2c0b5856677d256e3cfd

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: I739c72887617b026d80063fe1fab57f95124d508
Related: #25113
Fixes: #45833
Releases: 6.1, 6.0, 4.7, 4.6, 4.5
Reviewed-on: https://review.typo3.org/18941
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn