[sonic-utilities] Update submodule (sonic-net#8237)

This update includes the following commits

acb5d84 Neetha John     2021-07-20      [configlet] Python3 compatible syntax for extracting a key from the dict (sonic-net#1721)
9b7c58b arlakshm        2021-07-20      Load the  database global_db only once for show cli  (sonic-net#1712)

Signed-off-by: Arvindsrinivasan Lakshmi Narasimhan <arlakshm@microsoft.com>