kernel-shark: Fix a warning from 'KsUtils.cpp'

gcc 11.2.1 prints the following warning:

KsUtils.cpp:573:41: warning: loop variable 'task' creates a copy from
type 'const QString' [-Wrange-loop-construct]

Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>