Fixes Image timestamp calculation (#5988)

According to the docs `Created`  is `integerDate and time at which the image was created as a Unix timestamp (number of seconds sinds EPOCH)`

Fixes #4275

Author: leblonk

core/src/main/java/org/testcontainers/images/ImageData.java

@@ -24,6 +24,6 @@ static ImageData from(InspectImageResponse inspectImageResponse) {
     }
 
     static ImageData from(Image image) {
-        return ImageData.builder().createdAt(Instant.ofEpochMilli(image.getCreated())).build();
+        return ImageData.builder().createdAt(Instant.ofEpochSecond(image.getCreated())).build();
     }
 }