BUG/MEDIUM: tcp-rules: Fix track-sc* actions for L4/L5 TCP rules

BUG/MEDIUM: tcp-rules: Fix track-sc* actions for L4/L5 TCP rules

A bug was introduced during TCP rules refactoring by the commit ac98d81f4
("MINOR: http-rule/tcp-rules: Make track-sc* custom actions"). There is no
stream when L4/L5 TCP rules are evaluated. For these rulesets, In track-sc*
actions, we must take care to rely on the session instead of the stream.

Because of this bug, any evaluation of L4/L5 TCP rules using a track-sc* action
leads to a crash of HAProxy.

No backport needed, except if the above commit is backported.