www/squid: Fix STACKTRACES build option

We used to use this wrapper:
https://github.com/squid-cache/squid/blob/SQUID_6_14/src/debug/Stream.h#L182
However it was removed for squid 7 in:
https://github.com/squid-cache/squid/commit/016c612a77ac4f880ec2ed35e1c8fa9a73c3a2dd

Stop using wrapper.

PR: 292154