Negative Commission Rates Accepted

Describe the bug
An issue has been identified in the Multivendor Admin Dashboard where the commission rates for vendors are accepting negative values.

To Reproduce
Steps to reproduce the behavior:

Log in to the Multivendor Admin Dashboard.
Navigate to the section where commission rates for vendors are configured.
Attempt to set a negative value for the commission rate.
Expected behavior
The system should prevent users from entering or saving negative values for commission rates, as negative rates are not valid in this context.

Screenshots
https://github.com/ninjas-code-official/food-delivery-multivendor/assets/152266796/1cbcd911-8f36-43bc-8de1-8498ea3b5a78

Desktop:

Browser: chrome

Start by locating the Multivendor Admin Dashboard entry point for configuring vendor commission rates and reproduce the negative-value behavior in Chrome. The work is done when negative commission rates are rejected and cannot be saved; add or update the relevant validation coverage if tests exist there.

索引モデルが issue の本文から書いたものです。