ftests/013: add pids controller format

ftests/013: add pids controller format

Starting Linux Kernel version 6.1, the pids controller added an new
interface file pids.peak. It was introduced by upstream commit
5251c6c436ed ("cgroup: add pids.peak interface for pids controller").
Append a new expected output with the interface 'pids.peak' to cgroup v1
and v2 valid output.

-----------------------------------------------------------------
Test Results:
        Run Date:                          Apr 04 10:11:31
        Passed:                                  1 test(s)
        Skipped:                                 0 test(s)
        Failed:                                  0 test(s)
-----------------------------------------------------------------
Timing Results:
        Test                              Time (sec)
        --------------------------------------------
        setup                                   0.00
        013-cgget-multiple_g_flags.py           0.12
        teardown                                0.00
        --------------------------------------------
        Total Run Time                          0.12

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>