[TASK] Improve show_item for FAL files

The show_item.php shows some info about the selected file.
the property size is rendered twice, once in the
header section with a size (eg. 223kb) and below with
the size as byte. remote the last one.

A call to trim() can be removed as trimExplode() is used before

Change-Id: I33b0d9270bc6f81d490348c050c2b9e30c4a102c
Resolves: #41291
Releases: 6.0
Reviewed-on: http://review.typo3.org/14964
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe
Reviewed-by: Wouter Wolters
Reviewed-by: Andreas Wolf
Tested-by: Andreas Wolf