use common flag to allow test 3 for PS and ITS

add a compilation flag to allow tests which fill up the entire device storage.
storage test 003 (for both PS and its) is unsuitable for the regular CI because:
1. it takes a long time causing timeouts
2. it places a very high attrition load on the storage of the CI boards
    and this can cause them to fail much sooner.

Author: Nir Sonnenschein

components/TARGET_PSA/TESTS/compliance_its/test_s003/main.c

@@ -2,12 +2,13 @@
 #include "pal_mbed_os_intf.h"
 #include "lifecycle.h"
 
-#ifdef ITS_TEST
-void test_entry_s003(val_api_t *val_api, psa_api_t *psa_api);
-#elif PS_TEST
 #ifndef PS_ALLOW_ENTIRE_STORAGE_FILL
 #error [NOT_SUPPORTED] Test is too long for CI, thus always fails on timeout.
 #endif
+
+#ifdef ITS_TEST
+void test_entry_s003(val_api_t *val_api, psa_api_t *psa_api);
+#elif PS_TEST
 void test_entry_p003(val_api_t *val_api, psa_api_t *psa_api);
 #endif