fix(esp-tls): close CA-verification bypass during session resumption

The session-resumption else-if in set_client_config() short-circuited
the CA verification chain when only client_session was supplied. Remove
the branch so session-only configs fall through to the normal error /
skip-verify path; resumption no longer silently disables CA validation.

components/esp-tls/esp_tls_mbedtls.c

@@ -974,10 +974,6 @@ esp_err_t set_client_config(const char *hostname, size_t hostlen, esp_tls_cfg_t
             ESP_INT_EVENT_TRACKER_CAPTURE(tls->error_handle, ESP_TLS_ERR_TYPE_MBEDTLS, -ret);
             return ESP_ERR_MBEDTLS_SSL_CONF_PSK_FAILED;
         }
-#endif
-#ifdef CONFIG_ESP_TLS_CLIENT_SESSION_TICKETS
-    } else if (cfg->client_session != NULL) {
-        ESP_LOGD(TAG, "Reusing the saved client session");
 #endif
     } else {
 #ifdef CONFIG_ESP_TLS_SKIP_SERVER_CERT_VERIFY