test(lwip): Added LWIP_DHCP_RESTORE_LAST_IP config in lwip test apps

Enabled CONFIG_LWIP_DHCP_RESTORE_LAST_IP configuration to compile and
test the DHCP last IP restore functionality in CI tests.

Author: abhik-roy85

components/lwip/test_apps/main/CMakeLists.txt

@@ -1,4 +1,4 @@
 idf_component_register(SRCS "lwip_test.c"
                        REQUIRES test_utils
                        INCLUDE_DIRS "."
-                       PRIV_REQUIRES unity lwip test_utils)
+                       PRIV_REQUIRES unity lwip test_utils nvs_flash)

components/lwip/test_apps/sdkconfig.defaults

@@ -1,2 +1,5 @@
 CONFIG_UNITY_ENABLE_FIXTURE=y
 CONFIG_UNITY_ENABLE_IDF_TEST_RUNNER=n
+
+# Added to enable compilation of DHCP last IP restore feature
+CONFIG_LWIP_DHCP_RESTORE_LAST_IP=y