Inherit description of resource-derived parameter

**Is your feature request related to a problem? Please describe.**
Properties of a resource-derived parameter inherits attributes like minLength and description and so I'd expected that the description of the parameter will also be inherited.

On creation of the param it has a description:

But when the param is used in a bicepparam, the description is lost:

**Describe the solution you'd like**
1) Inherit the description by default, unless you'd decide to provide your own.

Or

2) Make description text nullable, like: `@description()` so you explicitly express that you want a description.

Start by tracing how descriptions and other attributes are propagated from resource-derived parameters into bicepparam usage; the issue names no source files or tests. Confirm the chosen inheritance or override behavior with a regression test covering the displayed scenario.

Written by the indexing model from the issue text.