rtla/actions: Restore continue flag in actions_perform()

rtla/actions: Restore continue flag in actions_perform()

Currently, actions_perform() only ever sets the continue flag (when
performing the continue action), but never resets it. That leads to
RTLA continuing tracing even if the continue action was not performed in
the current iteration.

For example, the following command:

$ rtla timerlat hist -T 100 --on-threshold shell,command='
    echo Spike!
    if [ -f /tmp/a ]
    then
      exit 1
    else
      touch /tmp/a
    fi' --on-threshold continue

should print Spike! at most once, because after hitting the threshold
for the first time, /tmp/a exists, the shell action will fail, and the
continue action is not performed. However, unless /tmp/a exists before
the measurement, it will print Spike! until stopped, as the continue
flag stays set.

Set the continue flag to false in the beginning of actions_perform() to
make RTLA continue only if the action was actually performed.

Fixes: 8d933d5c89e8 ("rtla/timerlat: Add continue action")
Link: https://lore.kernel.org/r/20260526102523.2662391-1-tglozar@redhat.com
[ correct Fixes tag to include 12 characters of hash ]
Signed-off-by: Tomas Glozar <tglozar@redhat.com>