Confirmation of amp-pixel and amp-analytics support with Chrome blocking 3rd party cookies in 2022

## Describe the new feature or change to an existing feature you'd like to see
amp-pixel and amp-analytics will continue to work and support existing functionality once Chrome blocks 3rd party cookies. For example, in amp-pixel, the src url is using a doubleclick floodlight pixel to track views. I'd like to understand if it'll continue to work.

## Describe alternatives you've considered

Provide a clear and concise description of any alternative solutions or features you've considered.

There isn't an alternative yet. Google Privacy Sandbox is not yet in production for use.

## Additional context

Add any other context or screenshots about the feature request here.

Start by reviewing the amp-pixel and amp-analytics components and how their existing functionality depends on third-party cookies. Check the reported Chrome blocking scenario and determine whether current support can be confirmed or what change is required. Done means the behavior under Chrome's cookie restrictions is established and any necessary scope is clearly identified.

Written by the indexing model from the issue text.