This is a follow-up to https://github.com/nushell/nushell/pull/8379 and
https://github.com/nushell/nushell/discussions/8502.
This PR makes it so that the new `?` syntax for marking a path member as
optional short-circuits, as voted on in the
[8502](https://github.com/nushell/nushell/discussions/8502) poll.
Previously, `{ foo: 123 }.bar?.baz` would raise an error:
```
> { foo: 123 }.bar?.baz
× Data cannot be accessed with a cell path
╭─[entry #15:1:1]
1 │ { foo: 123 }.bar?.baz
· ─┬─
· ╰── nothing doesn't support cell paths
╰────
```
Here's what was happening:
1. The `bar?` path member access returns `nothing` because there is no field named `bar` on the record
2. The `baz` path member access fails when trying to access a `baz` field on that `nothing` value
After this change, `{ foo: 123 }.bar?.baz` returns `nothing`; the failed `bar?` access immediately returns `nothing` and the `baz` access never runs.