Request to Enable Dynamic Source Binding [src] in amp-list for AMP Email

### Description

I would like to propose the addition of dynamic source binding using the [src] attribute in the amp-list component within AMP for Email. Currently, AMP for Email restricts the use of amp-bind for dynamic content updates, limiting interactive capabilities in email applications, particularly those that require real-time data updates such as live feeds. Enabling this feature would greatly enhance the interactivity and functionality of AMP emails by allowing more dynamic and responsive elements within emails.

The primary use case for this feature is in applications like dynamic personalized content updates directly within an email without needing to reload or revisit webpages. This enhancement would align AMP Email more closely with modern web app capabilities, improving user engagement and the overall utility of AMP in email.

### Alternatives Considered

Currently, to achieve dynamic updates, developers must use amp-form to submit requests and then manually trigger a refresh of the amp-list content. While this workaround is functional, it's not as efficient or seamless as having support for [src] binding. Another alternative is server-side rendering of updates, but this requires frequent server calls for every small change, increasing server load and potentially leading to slower user experiences. It's also possible to argue that this could put users data and privacy in the harms way.

Expected Benefits:

Enhanced user interactivity and engagement within emails.
Reduced complexity and overhead in implementing dynamic content updates.
Additional Considerations:
This feature should be implemented with consideration for security and performance implications, ensuring that it does not compromise user safety or email deliverability.

Conclusion:
By enabling [src] binding in amp-list for AMP Emails, we can significantly improve the interactivity and functionality of AMP-powered emails, making them a more robust platform for modern email applications.

### Additional Context

_No response_

Start by reviewing the amp-list component and AMP for Email restrictions around amp-bind [src], then compare the existing amp-form refresh workaround. A viable outcome needs a scoped design addressing security, performance, privacy, and email deliverability before implementation details and validation coverage can be defined.

Written by the indexing model from the issue text.