Some images are missing default selected attribute for keyboard-select-mode in <amp-selector> component

### Description

Some images are missing default selected attribute for keyboard-select-mode in amp-selector component

### Reproduction Steps

1. Opt into needed version of AMP via https://cdn.ampproject.org/experiments.html
2. Open browser console and verify that you are on the right version of amp
3. Go through the provided link https://playground.amp.dev/?url=https%3A%2F%2Fpreview.amp.dev%2Fdocumentation%2Fexamples%2Fcomponents%2Famp-selector&format=websites&_gl=1*1kgsbzt*_ga*YW1wLW83ZWlnQnRSNnV0d0lWS2dEWG1YSmc.
4. Select any images and checkboxes except blurry images

Actual result: Some images are missing default selected attribute for keyboard-select-mode and are not getting selected when clicked on them
http://screencast/cast/NTk0ODE3MDc4NjgzMjM4NHwyNjMzNDk5ZC0xNw

Expected result: Images and checkboxes should be selected except blurry images.

Environment:
Browsers: Chrome (113.0.5672.92), Firefox (113.0.1), Safari (14.6)
Device: Macbook Pro, iPhone XR, Pixel 3a XL

### Relevant Logs

_No response_

### Browser(s) Affected

_No response_

### OS(s) Affected

_No response_

### Device(s) Affected

_No response_

### AMP Version Affected

_No response_