build(core): fix build for GCC13

we need to cherry-pick two commits into the micropython submodule, and
adapt one of the fixes

Author: matejcik

core/embed/unix/main.c

@@ -682,9 +682,9 @@ MP_NOINLINE int main_(int argc, char **argv) {
 #if !MICROPY_VFS
 
 #ifdef TREZOR_EMULATOR_FROZEN
-uint mp_import_stat(const char *path) { return MP_IMPORT_STAT_NO_EXIST; }
+mp_import_stat_t mp_import_stat(const char *path) { return MP_IMPORT_STAT_NO_EXIST; }
 #else
-uint mp_import_stat(const char *path) {
+mp_import_stat_t mp_import_stat(const char *path) {
   struct stat st;
   if (stat(path, &st) == 0) {
     if (S_ISDIR(st.st_mode)) {