Allow configuration of health check polling interval in Aspire Dashboard

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Is your feature request related to a problem? Please describe the problem.

The Aspire Dashboard currently polls service health endpoints (e.g., /health) at a fixed internal interval. However, this interval is not configurable.

This can result in frequent health check requests to services, which may not be desirable in certain scenarios (e.g., expensive health checks or limited system resources).

Feature Request:
Please provide a way to configure the health check polling interval per service or globally in the Aspire Dashboard. Ideally, this could be done via:

### Describe the solution you'd like

A method on builder.AddProject(...).WithHealthOptions(...)

Or a dashboard-level configuration file or environment variable

Use Case:
As a developer, I want to reduce the frequency of health check requests made by Aspire Dashboard during development to avoid unnecessary load on services or throttling responses.

Workaround:
I’m currently throttling the /health endpoint manually using in-memory caching in the service, but it would be more elegant and efficient to control this from Aspire itself.

### Additional context

_No response_