Convert utility functions to TypeScript (#22658)

* Convert event-tracking to TypeScript

* Convert local-storage to TypeScript

* Convert mapSeries to TypeScript

* Convert SessionStorage to TypeScript

* Convert account-upgrade to TypeScript

* Convert isValidTeXFile to TypeScript

* Convert date functions to TypeScript

* Convert EventEmitter to TypeScript

* Convert isNetworkError to TypeScript

* Convert webpack-public-path to TypeScript

* Convert displayNameForUser to TypeScript

GitOrigin-RevId: 79c5a2d1101fcd520f3116f0f4af29d974189d94

services/web/types/window.ts

@@ -37,5 +37,7 @@ declare global {
         store: ScopeValueStore
       }
     }
+    ga?: (...args: any) => void
+    gtag?: (...args: any) => void
   }
 }