AMP Optimizer shouldn’t strip `sizes` without `srcset`

In `packages/optimizer/lib/transformers/ApplyCommonAttributes.js` line 81-83, the optimizer strips the `sizes` attribute when `srcset` is not also present. Here is the related comment in the code::

> // According to the Mozilla docs, a sizes attribute without a valid srcset attribute should have no effect.
> // Therefore, it should simply be stripped, without producing media queries.
> // @see https://developer.mozilla.org/en-US/docs/Web/HTML/Element/img#attr-sizes

But for AMP elements, `sizes` has a bigger meaning; see "Sizes" on https://amp.dev/documentation/guides-and-tutorials/learn/amp-html-layout/?format=websites

Stripping it causes some amp elements to size incorrectly after server-side-rendering is applied.

Start in packages/optimizer/lib/transformers/ApplyCommonAttributes.js at lines 81-83, then read the linked AMP layout "Sizes" documentation alongside the Mozilla reference. Confirm how AMP elements use sizes without srcset in server-side rendering; done means those sizes are preserved where needed and the incorrect sizing is no longer introduced.

Written by the indexing model from the issue text.