Play Rate slider can only go up to 3966 instead of the 4000 set maximum when the VFX Control overlay is small

Steps to reproduce:

1. Create a new Unity project using the Universal 3D template
2. Install the Visual Effect Graph package (com.unity.visualeffectgraph)
3. Create a new VFX Graph (Assets > Create > Visual Effects > Visual Effect Graph)
4. Open the newly created VFX Graph
5. Drag the created VFX Graph asset into the Hierarchy window and make sure its selected
6. Enable the VFX Control overlay in the VFX Graph window
7. Resize the VFX Control overlay to the minimum size
8. Change the Play Rate via the slider to the maximum value in the VFX Control overlay
9. Observe the Play Rate

Actual results: The Slider's maximum selected value is 3966

Expected results: The maximum selected value is 4000

Reproducible with versions: 2023.1.0a3, 6000.0.73f1, 6000.3.14f1, 6000.4.4f1, 6000.5.0b5, 6000.6.0a3

Tested on (OS): MacOS Silicon Tahoe 26.3, Ubuntu 24.04

Notes:

• Slider works as intended when the VFX Control overlay is bigger size