Save item button on the Dandiset contributors form is unreachable with 125 % browser zoom

I originally reported this on Slack, but I wanted to provide a more detailed version here for documentation.

When saving a Person entry in the Dandiset contributor metadata form, I ran into two problems:

1. **“Save item” button not visible**
At my browser zoom level (125%), the “Save item” button is hidden and cannot be reached.
- Around the 20-second mark in the video below, you can see me trying to scroll to access it, but there’s no way to reach that area.
- Even worse, a user at this zoom level would never know the button exists at all.

2. **Floppy disk icon saves empty entries**
The floppy disk icon becomes available, but clicking it always saves an empty item. This was confusing because I initially thought it was the correct way to save the entry. Since the saved item was empty, it gave me the impression that the save process was failing for unknown reasons. At the end of the video, note how clicking the floppy disk saves an empty entry even if “Save item” was never clicked.

You can see both issues in the following video where I have added a key cast to

https://github.com/user-attachments/assets/0a2516c7-f1be-4a30-8ce5-0f05209ff71b

```bash
xrandr

Screen 0: minimum 8 x 8, current 3640 x 1920, maximum 32767 x 32767
DP-0 connected 1080x1920+0+0 right (normal left inverted right x axis y axis) 527mm x 296mm
1920x1080 60.00*+ 74.97 59.94 50.00
1680x1050 59.95
1440x900 59.89
1280x1024 75.02 60.02
1280x960 60.00
1280x720 60.00 59.94 50.00
1024x768 75.03 70.07 60.00
800x600 75.00 72.19 60.32 56.25
720x576 50.00
720x480 59.94
640x480 75.00 72.81 59.94 59.93

HDMI-0 connected primary 2560x1440+1080+0 (normal left inverted right x axis y axis) 698mm x 393mm
2560x1440 59.95*+ 74.78
1920x1200 59.88
1920x1080 60.00 59.94 50.00
1680x1050 59.95
1440x900 59.89
1280x1024 75.02 70.00 60.02
1280x720 60.00 59.94 50.00
1152x864 75.00
1024x768 75.03 70.07 60.00
800x600 75.00 72.19 60.32
720x576 50.00
720x480 59.94
640x480 75.00 72.81 59.94 59.93
DP-4 connected (normal left inverted right x axis y axis)
2560x1600 60.00 + 165.00
```

Start by reproducing the Dandiset contributor metadata form issue at 125% browser zoom, focusing on saving a Person entry. Verify that the “Save item” control is reachable and that the floppy disk action preserves the entered data rather than saving an empty item; done means both actions behave clearly and correctly at that zoom level.

Written by the indexing model from the issue text.