Add 2 missing `throw error_already_set();` (#4863)

Fixes oversights in PR #4570.

include/pybind11/detail/internals.h

@@ -451,6 +451,7 @@ inline object get_python_state_dict() {
 #endif
     if (!state_dict) {
         raise_from(PyExc_SystemError, "pybind11::detail::get_python_state_dict() FAILED");
+        throw error_already_set();
     }
     return state_dict;
 }
@@ -463,6 +464,7 @@ inline internals **get_internals_pp_from_capsule(handle obj) {
     void *raw_ptr = PyCapsule_GetPointer(obj.ptr(), /*name=*/nullptr);
     if (raw_ptr == nullptr) {
         raise_from(PyExc_SystemError, "pybind11::detail::get_internals_pp_from_capsule() FAILED");
+        throw error_already_set();
     }
     return static_cast<internals **>(raw_ptr);
 }