Refactor FXIOS [Nimbus] Update initial experiments JSON for Nimbus (#29397)

update initial_experiments.json based on the current first-run experiments in experimenter

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

firefox-ios/Client/Experiments/initial_experiments.json

@@ -312,7 +312,7 @@
       "channel": "release",
       "userFacingName": "iOS Search Middle Homescreen",
       "userFacingDescription": "Search in Middle of Homescreen",
-      "isEnrollmentPaused": false,
+      "isEnrollmentPaused": true,
       "isRollout": false,
       "bucketConfig": {
         "randomizationUnit": "nimbus_id",
@@ -385,7 +385,7 @@
       ],
       "targeting": "((is_already_enrolled) || ((isFirstRun == 'true') && (app_version|versionCompare('142.1.0') >= 0)))",
       "startDate": "2025-08-14",
-      "enrollmentEndDate": null,
+      "enrollmentEndDate": "2025-09-17",
       "endDate": null,
       "proposedDuration": 28,
       "proposedEnrollment": 14,
@@ -621,20 +621,20 @@
     },
     {
       "schemaVersion": "1.12.0",
-      "slug": "summarizer-mistral-model-rollout-first-run-new-users-us",
-      "id": "summarizer-mistral-model-rollout-first-run-new-users-us",
+      "slug": "summarizer-mistral-model-rollout-first-run-new-users",
+      "id": "summarizer-mistral-model-rollout-first-run-new-users",
       "arguments": {},
       "application": "org.mozilla.ios.Firefox",
       "appName": "firefox_ios",
       "appId": "org.mozilla.ios.Firefox",
       "channel": "release",
-      "userFacingName": "Summarizer - Mistral Model Rollout First Run New Users US",
+      "userFacingName": "Summarizer - Mistral Model Rollout First Run New Users",
       "userFacingDescription": "Summarizer",
       "isEnrollmentPaused": false,
       "isRollout": true,
       "bucketConfig": {
         "randomizationUnit": "nimbus_id",
-        "namespace": "ios-hosted-summarizer-feature-release-mobile_new_users-rollout-1",
+        "namespace": "ios-hosted-summarizer-feature-release-mobile_new_users-rollout-2",
         "start": 0,
         "count": 10000,
         "total": 10000
@@ -666,8 +666,8 @@
           ]
         }
       ],
-      "targeting": "((is_already_enrolled) || ((days_since_install < 7) && (app_version|versionCompare('143.1.0') >= 0) && (language in ['en']) && (region in ['US']) && (('summarizer-mistral-model-full-rollout' in enrollments) == false) && ((enrollments_map['summarizer-mistral-model-rollout'] == 'treatment-a') == false)))",
-      "startDate": "2025-09-15",
+      "targeting": "((is_already_enrolled) || ((days_since_install < 7) && (app_version|versionCompare('143.!') >= 0) && (language in ['en']) && (region in ['US']) && (('summarizer-mistral-model-full-rollout' in enrollments) == false) && ((enrollments_map['summarizer-mistral-model-rollout'] == 'treatment-a') == false)))",
+      "startDate": "2025-09-17",
       "enrollmentEndDate": null,
       "endDate": null,
       "proposedDuration": 28,
@@ -676,7 +676,7 @@
       "featureValidationOptOut": false,
       "localizations": null,
       "locales": null,
-      "publishedDate": "2025-09-15T15:04:46.880374Z",
+      "publishedDate": "2025-09-17T19:20:28.247535Z",
       "isFirefoxLabsOptIn": false,
       "firefoxLabsTitle": "",
       "firefoxLabsDescription": "",