fix(log): fixed wrong year timestamp with LOG_TIMESTAMP_SOURCE_SYSTEM_FULL

struct tm contains the number of years since 1900, but the printing code
assumed it contained actual current year.

It would also print it as YYYY, while the documentation and code implies
it should be YY.

Closes espressif#17451

Author: ESP-Marius

components/log/src/log_timestamp_common.c

@@ -106,8 +106,9 @@ char* esp_log_timestamp_str(bool constrained_env, uint64_t timestamp_ms, char* b
         uint64_t msec = timestamp_ms % 1000;
         localtime_r(&sec, &timeinfo);
 #if CONFIG_LOG_TIMESTAMP_SOURCE_SYSTEM_FULL
+        uint32_t year = (timeinfo.tm_year + 1900) % 100;
         // it takes 22 bytes to output it in the format: "YY-MM-DD HH:MM:SS.sss"
-        buffer += esp_log_util_cvt_dec(timeinfo.tm_year, 2, buffer);
+        buffer += esp_log_util_cvt_dec(year, 2, buffer);
         *buffer++ = '-';
         buffer += esp_log_util_cvt_dec(timeinfo.tm_mon + 1, 2, buffer);
         *buffer++ = '-';