pjsua_init: Fix for format-truncation error with GCC 13.2.0.

[amubiera]

Fix for warning as error under GCC 13.2.0:

pjsip/src/pjsua-lib/pjsua_core.c:1357:61: error: ‘__builtin___snprintf_chk’ output may be truncated before the last format character [-Werror=format-truncation=]
 1357 |             pj_ansi_snprintf(tname, sizeof(tname), "pjsua_%d", ii);
      |                                                             ^

[Copilot]

Pull request overview

This PR addresses a GCC 13.2.0 -Wformat-truncation warning (treated as error) in pjsua_init() by increasing the size of the temporary thread-name buffer used when creating PJSUA worker threads.

Changes:

• Increase the local tname buffer size used for worker thread names from 16 to 32 bytes to avoid potential snprintf truncation warnings under GCC 13.2.0.