esp32: increase default event task stack size by 256 bytes

At debug log level, default event task stack size was not sufficient,
the stack was overflown by 232 bytes when WiFi connection happened.

components/esp32/Kconfig

@@ -281,7 +281,7 @@ config SYSTEM_EVENT_QUEUE_SIZE
 
 config SYSTEM_EVENT_TASK_STACK_SIZE
     int "Event loop task stack size"
-    default 2048
+    default 2304
     help
         Config system event task stack size in different application.