For #26414 - Have the Pocket spocs feature as part of the homescreen sections experiments

.experimenter.yaml

@@ -66,14 +66,6 @@ onboarding:
     sections-enabled:
       type: json
       description: This property provides a lookup table of whether or not the given section should be enabled.
-pocket-sponsored-stories:
-  description: A feature showing sponsored stories in between the other Pocket recommended stories on homescreen.
-  hasExposure: true
-  exposureDescription: ""
-  variables:
-    enabled:
-      type: boolean
-      description: "If true, the Pocket stories shown on homescreen should contain sponsored stories also."
 search-term-groups:
   description: A feature allowing the grouping of URLs around the search term that it came from.
   hasExposure: true

app/src/main/java/org/mozilla/fenix/utils/Settings.kt

@@ -1301,7 +1301,7 @@ class Settings(private val appContext: Context) : PreferencesHolder {
      */
     val showPocketSponsoredStories by lazyFeatureFlagPreference(
         key = appContext.getPreferenceKey(R.string.pref_key_pocket_sponsored_stories),
-        default = { FxNimbus.features.pocketSponsoredStories.value(appContext).enabled },
+        default = { homescreenSections[HomeScreenSection.POCKET_SPONSORED_STORIES] == true },
         featureFlag = FeatureFlags.isPocketSponsoredStoriesFeatureEnabled(appContext)
     )
 

nimbus.fml.yaml

@@ -19,6 +19,7 @@ features:
             "recently-saved": true,
             "recent-explorations": true,
             "pocket": true,
+            "pocket-sponsored-stories": false,
             "contile-top-sites": false,
           }
     defaults:
@@ -33,6 +34,12 @@ features:
             "contile-top-sites": false,
           }
         }
+      - channel: developer
+        value: {
+          "sections-enabled": {
+            "pocket-sponsored-stories": true,
+          }
+        }
   onboarding:
     description: The onboarding features displayed on homescreen.
     variables:
@@ -210,18 +217,6 @@ features:
         value:
           enabled: false
 
-  pocket-sponsored-stories:
-    description: A feature showing sponsored stories in between the other Pocket recommended stories on homescreen.
-    variables:
-      enabled:
-        description:  If true, the Pocket stories shown on homescreen should contain sponsored stories also.
-        type: Boolean
-        default: false
-    defaults:
-      - channel: developer
-        value:
-          enabled: true
-
   engine-settings:
     description: Contains a set of settings for controlling the web engine configurations.
     variables:
@@ -320,6 +315,8 @@ types:
           description: The tab groups
         pocket:
           description: The pocket section. This should only be available in the US.
+        pocket-sponsored-stories:
+          description: Subsection of the Pocket homescreen section which shows sponsored stories.
         contile-top-sites:
           description: The sponsored shortcuts in the homescreen.
     MessageSurfaceId: