Closes #1946 Embedded images in demo content are not found (#2995)

modules/custom/az_demo/data/az_demo_image_file.json

@@ -72,6 +72,7 @@
  "title": ""
  },
  {
+ "uuid": "5cec161c-71bc-4d23-824f-a692400ee17a",
  "filename" : "arizona_campus_fireworks.jpg",
  "alt" : "Fireworks over campus",
  "title": ""
@@ -151,6 +152,12 @@
  "filename" : "gmo.jpg",
  "alt" : "Concept of research on genetic modification of food",
  "title": ""
+ },
+ {
+ "filename" : "sea-anemone.jpg",
+ "alt" : "A close-up image of a vibrant sea anemone under water. The anemone's long, slender tentacles are colored in varying shades of blue and tipped with yellow, creating a striking contrast. Partially hidden among the tentacles, a clownfish with its characteristic orange and white stripes can be seen, adding a sense of life and movement to the scene. The background is a blur of marine colors, indicating a complex reef environment.",
+ "title" : "Clownfish Peekaboo in a Sea Anemone",
+ "uuid": "6c01643a-9935-4317-874f-5fd0a29fad26"
  }
  ]
 }

modules/custom/az_demo/migrations/az_demo_image_file.yml

@@ -18,6 +18,9 @@ source:
  type: string
 
  fields:
+ -
+ name: uuid
+ selector: uuid
  -
  name: filename
  selector: filename
@@ -31,6 +34,10 @@ source:
 destination:
  plugin: 'entity:media'
 process:
+ uuid:
+ plugin: skip_on_empty
+ method: process
+ source: uuid
  bundle:
  plugin: default_value
  default_value: az_image