change: bump max sockets in lwip Kconfig

Tested under ESP32S3, running 50 tasks, each with a client, and a server
listening to one client, totalizing 150 sockets/files open, forwarding
data from PPP to Ethernet and vice versa.
Reasoning for 255 total sockets/files is VFS local_fd_t being a uint8_t.
Since FD_SETSIZE is defined at tool level, a CMakeLists user definition
is needed in cases above 64 (the default value).

Merges #13866

components/lwip/Kconfig

@@ -135,13 +135,19 @@ menu "LWIP"
 
     config LWIP_MAX_SOCKETS
         int "Max number of open sockets"
-        range 1 16
+        range 1 253
         default 10
         help
+            The practical maximum limit is
+            determined by available heap memory at runtime.
+
             Sockets take up a certain amount of memory, and allowing fewer
             sockets to be open at the same time conserves memory. Specify
             the maximum amount of sockets here. The valid value is from 1
-            to 16.
+            to 253. If using value above 61, update CMakeLists defining
+            FD_SETSIZE to the number of sockets used plus the
+            expected open files (minimum of +3 for stdout, stderr and stdin).
+
 
     config LWIP_USE_ONLY_LWIP_SELECT
         bool "Support LWIP socket select() only (DEPRECATED)"

tools/ci/check_public_headers_exceptions.txt

@@ -68,7 +68,6 @@ components/json/cJSON/
 components/spiffs/include/spiffs_config.h
 
 components/unity/unity/src/unity_internals.h
-components/unity/unity/extras/
 components/unity/include/unity_config.h
 components/unity/include/unity_test_runner.h