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

This reverts commit 9938efcc3d4e7f7609b8aeaa733108c63e212601

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: I7ab3344e27ebec2a4532e387e29a8507f4cb7d4f
Related: #25113
Fixes: #45833
Releases: 6.1, 6.0, 4.7, 4.6, 4.5
Reviewed-on: https://review.typo3.org/18945
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn