[no-relnote] fix e2e failures for nvidia-container-cli test cases

Newer versions of Ubuntu container images (starting with 26.04)
introduced changes that broke nvidia-container-cli tests.
In particular, the libcap shared library, the pivot_root binary,
and /sbin/ldconfig.real are not included by default. This differs
from prior releases. To account for this and fix the test failures,
the libcap2 and utils-linux-extra (provided pivot_root) packages
have been added as prerequisites that get installed in the
nested container runner used in our e2e tests. In addition,
/sbin/ldconfig.real is made a symlink to /sbin/ldconfig if
it doesn't exist.

Signed-off-by: Christopher Desiniotis <cdesiniotis@nvidia.com>