Datetime auto-opening on Webkit/Safari

### I'm Submitting a ...
```
[x] Bug report
[ ] Feature request
[ ] Support request
```

### Steps to Reproduce
1. Open Safari (I'm using version 17.5)
2. Instantiate a `` with `open={undefined}`, `inputProps={{someProps}}`, `renderInput={someJsx}`, specifically not specifying the `input` prop.
3. See that the input is focused and the date picker menu is open

### Expected Results
That the menu starts closed when `open={undefined}`

### Actual Results
The menu is open

### Minimal Reproduction of the Problem
Couldn't seem to get the codepen to work.

### Other Information (e.g. stacktraces, related issues, suggestions how to fix)
I can see the default open state is being set in DateTime#getInitialState to `open: !props.input`, which does not consider the `open` prop. I would expect the default open state to just be `open: props.open`

Start by locating DateTime#getInitialState and inspect how the open prop is handled when input is omitted and open is undefined. Reproduce the case in Safari 17.5, then verify that the datetime menu remains closed in that configuration and that existing behavior is preserved.

Written by the indexing model from the issue text.