When creating a new provider, custom endpoints added in the speed test
modal were not being saved properly. The issue was in ProviderForm.tsx
where the CustomEndpoint object was constructed without the optional
lastUsed field.
This caused inconsistency between:
- Edit mode: uses backend API (addCustomEndpoint) which correctly
constructs complete CustomEndpoint objects
- Create mode: directly constructs objects in frontend, missing the
lastUsed field
Fixed by explicitly setting lastUsed to undefined when constructing
custom endpoints in create mode, ensuring structural consistency with
the TypeScript CustomEndpoint interface.