[amp-script]Allow 'amp-script' to appear in descendants of 'amp-script'

### Description

I added custom javascript to a component with amp-script.
In addition, I wanted to use amp-script to add custom javascript to a more extensive dom containing that component, but I got the following error.
> The tag 'amp-script' may not appear as a descendant of tag 'amp-script'.

Please consider allowing amp-script descendants to have amp-script.

### Alternatives Considered

none

### Additional Context

_No response_

No files or tests are identified in the issue. Start by locating the validation that emits the nested amp-script error and determine the intended behavior for descendant components. Done should include support for the requested nesting and coverage proving that valid descendants are accepted.

Written by the indexing model from the issue text.