Does not work with wp_filter_content_tags filter.

When using the plugin, image blocks inserted through Gutenberg do not get the `srcset` and `sizes` attributes automatically populated as it does on the main site using [wp_filter_content_tags](https://github.com/WordPress/WordPress/blob/1020306fe96172a74532378bf1d4e79da67e8b4b/wp-includes/media.php#L1771).

The first reason this doesn't happen is because the image blocks do not have the `width` and `height` attributes set and thus fails [ the following conditional](https://github.com/WordPress/WordPress/blob/1020306fe96172a74532378bf1d4e79da67e8b4b/wp-includes/media.php#L1684). If the width/height attributes were present, it would work.

Even without the attributes, WordPress should be able to autodetect the dimensions based on the postmeta, but fails because it's comparing the the image filename to a full remote URL and thus [this conditional](https://github.com/WordPress/WordPress/blob/1020306fe96172a74532378bf1d4e79da67e8b4b/wp-includes/media.php#L1620) also fails.

A quick fix on my end was the following filter:

```php
add_filter('wp_image_src_get_dimensions', function ($dimensions, string $image_src, array $image_meta, int $attachment_id) {
if ($dimensions !== false || empty($image_meta['sizes'])) {
return $dimensions;
}

$src_filename = wp_basename($image_src);

foreach ($image_meta['sizes'] as $image_size_data) {
// Check for AMF remote URLs
if (filter_var($image_size_data['file'], FILTER_VALIDATE_URL) === false) {
continue;
}

// Compare against the filename rather than the full URL.
$image_size_filename = wp_basename($image_size_data['file']);
if ($src_filename === $image_size_filename) {
$dimensions = [
(int) $image_size_data['width'],
(int) $image_size_data['height'],
];
break;
}
}
return $dimensions;
}, 10, 4);
```

_I'm guessing the correct fix for this would be to set the `width`/`height` attributes on the image tag when inserted with Gutenberg. I have not looked into why this is happening._

If it matters, I noticed that postmeta of the attachment had the `file` property set to the filename, not the year-month relative path (in case you do not use year-month folders when testing this).
So the sub site has the `file` property set to `Car-at-beach.png` while the remote site has it set to `2021/10/Car-at-beach.png`