Update C-S-S to 7.4.0 (#1153)

Task/Issue URL: https://app.asana.com/0/72649045549333/1209115970418978/f

Description:
This change bumps C-S-S to the version including recent fixes for HTML New Tab Page
(assorted macOS Big Sur fixes, customizer panel fixes and gradient background fixes).

Package.resolved

@@ -14,8 +14,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/duckduckgo/content-scope-scripts",
       "state" : {
-        "revision" : "a539758027d9fd37d9d26213399ac156ca9fb81c",
-        "version" : "7.1.0"
+        "revision" : "06d244c4e0951ef16217c46f23c4865c5f98dd5c",
+        "version" : "7.4.0"
       }
     },
     {
@@ -77,8 +77,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/swift-concurrency-extras",
       "state" : {
-        "revision" : "163409ef7dae9d960b87f34b51587b6609a76c1f",
-        "version" : "1.3.0"
+        "revision" : "82a4ae7170d98d8538ec77238b7eb8e7199ef2e8",
+        "version" : "1.3.1"
       }
     },
     {

Package.swift

@@ -55,7 +55,7 @@ let package = Package(
         .package(url: "https://github.com/duckduckgo/TrackerRadarKit", exact: "3.0.0"),
         .package(url: "https://github.com/duckduckgo/sync_crypto", exact: "0.3.0"),
         .package(url: "https://github.com/gumob/PunycodeSwift.git", exact: "3.0.0"),
-        .package(url: "https://github.com/duckduckgo/content-scope-scripts", exact: "7.1.0"),
+        .package(url: "https://github.com/duckduckgo/content-scope-scripts", exact: "7.4.0"),
         .package(url: "https://github.com/duckduckgo/privacy-dashboard", exact: "7.5.0"),
         .package(url: "https://github.com/httpswift/swifter.git", exact: "1.5.0"),
         .package(url: "https://github.com/duckduckgo/bloom_cpp.git", exact: "3.0.0"),