feat(Classic Search): match icon colour with Classic Footer

Author: AprilSylph

src/features/classic_search/feature.json

@@ -4,7 +4,7 @@
   "icon": {
     "class_name": "ri-search-line",
     "color": "white",
-    "background_color": "#f7650d"
+    "background_color": "#395875"
   },
   "help": "https://github.com/AprilSylph/XKit-Rewritten/wiki/Features#classic-search",
   "preferences": {