Remove site history dropdown and update Electron

Eliminated the custom site history dropdown UI and its related event handlers from script.js. Updated Electron to version 37.2.4 in package.json and package-lock.json. Cleared entries from search-history.json and site-history.json.

package-lock.json

@@ -9,7 +9,7 @@
       "version": "1.0.0",
       "license": "ISC",
       "devDependencies": {
-        "electron": "^37.2.3",
+        "electron": "^37.2.4",
         "electron-builder": "^23.0.0"
       }
     },
@@ -1386,9 +1386,9 @@
       }
     },
     "node_modules/electron": {
-      "version": "37.2.3",
-      "resolved": "https://registry.npmjs.org/electron/-/electron-37.2.3.tgz",
-      "integrity": "sha512-JRKKn8cRDXDfkC+oWISbYs+c+L6RA776JM0NiB9bn2yV8H/LnBUlVPzKKfsXgrUIokN4YcbCw694vfAdEJwtGw==",
+      "version": "37.2.4",
+      "resolved": "https://registry.npmjs.org/electron/-/electron-37.2.4.tgz",
+      "integrity": "sha512-F1WDDvY60TpFwGyW+evNB5q0Em8PamcDTVIKB2NaiaKEbNC2Fabn8Wyxy5g+Anirr1K40eKGjfSJhWEUbI1TOw==",
       "dev": true,
       "hasInstallScript": true,
       "license": "MIT",