remove dark & transp from pref JSON

it's never used and doesn't support the system theme (which is now the
default)

Author: ornicar

doc/specs/examples/account-getMyPreferences.json.yaml

@@ -2,8 +2,6 @@ value:
   {
     "prefs":
       {
-        "dark": true,
-        "transp": false,
         "bgImg": "https://lichess1.org/assets/lifat/background/gallery/bg10.webp",
         "is3d": false,
         "theme": "brown",

doc/specs/schemas/BroadcastRoundInfo.yaml

@@ -7,12 +7,6 @@ properties:
     type: string
   slug:
     type: string
-  createdAt:
-    type: integer
-    format: int64
-  rated:
-    type: boolean
-    description: "Whether the round is used for rating calculations"
   ongoing:
     type: boolean
   startsAt:
@@ -27,12 +21,13 @@ properties:
   finished:
     type: boolean
     deprecated: true
+    description: "Use finishedAt instead"
   url:
     type: string
     format: uri
-  delay:
-    type: integer
-    format: int64
+  rated:
+    type: boolean
+    description: "Whether the round is used for rating calculations"
   customScoring:
     $ref: "./BroadcastCustomScoring.yaml"
 
@@ -41,4 +36,3 @@ required:
   - name
   - slug
   - url
-  - createdAt

doc/specs/schemas/UserPreferences.yaml

@@ -1,9 +1,5 @@
 type: object
 properties:
-  dark:
-    type: boolean
-  transp:
-    type: boolean
   bgImg:
     type: string
     format: uri