Ignore `layer does not exist` error from `docker images`
Fix #31350
As we can see in `daemon.Images()`, there is a gap between
`allImages = daemon.imageStore.Map()` and `l, err :=
daemon.layerStore.Get(layerID)`, so images which still exist when we hit
`allImages = daemon.imageStore.Map()` may have already been deleted when we hit
`l, err := daemon.layerStore.Get(layerID)`.
```
if danglingOnly {
allImages = daemon.imageStore.Heads()
} else {
allImages = daemon.imageStore.Map()
}
...
for id, img := range allImages {
...
layerID := img.RootFS.ChainID()
var size int64
if layerID != "" {
l, err := daemon.layerStore.Get(layerID)
if err != nil {
return nil, err
}
```
Signed-off-by: Yuanhong Peng <pengyuanhong@huawei.com>