fix(telemetry): register React and ReactFire versions at import time (#835)

ReactFire registered the React and ReactFire versions with Firebase only
when FirebaseAppProvider initialized a new app from firebaseConfig. Apps
that passed firebaseApp, reused an initialized app, or called hooks
without the provider reported no React or ReactFire version.

src/telemetry.ts adds registerReactFireVersion, which registers both
versions with registerVersion and runs at import time.
FirebaseAppProvider (ahead of its early returns) and useObservable also
call it as a fallback.

Firebase's heartbeat records the registered versions once per UTC day,
at the first _getProvider call (the first getFirestore(), getAuth(), and
so on). Registering at import time therefore covers apps that create SDK
instances at module scope, unless their entry file imports that setup
before ReactFire. Those apps still go uncounted, so heartbeat counts are
a lower bound.

registerReactFireVersion checks Firebase's internal _components map
before registering, so repeated calls do not log "There were multiple
attempts to register component" at debug level. If that map is
unavailable, a module-level flag prevents repeat calls instead. The
function never throws, so a partially mocked or badly bundled
firebase/app cannot break importing or rendering ReactFire.

Author: jhuleatt

docs/reference/functions/FirebaseAppProvider.md

@@ -1,9 +1,10 @@
 import * as React from 'react';
-import { getApps, initializeApp, registerVersion } from 'firebase/app';
+import { getApps, initializeApp } from 'firebase/app';
+import { registerReactFireVersion, version } from './telemetry.js';
 
 import type { FirebaseApp, FirebaseOptions } from 'firebase/app';
 
-declare const process: { env: Record<string, string | undefined> };
+export { version };
 
 // INVESTIGATE I don't like magic strings, can we have export this in js-sdk?
 const DEFAULT_APP_NAME = '[DEFAULT]';
@@ -18,15 +19,14 @@ export interface FirebaseAppProviderProps {
   suspense?: boolean;
 }
 
-// REACTFIRE_VERSION is automatically pulled in from `package.json` by Vite
-export const version = process.env.REACTFIRE_VERSION as string;
-
 const shallowEq = (a: { [key: string]: any }, b: { [key: string]: any }) => a === b || [...Object.keys(a), ...Object.keys(b)].every((key) => a[key] === b[key]);
 
 export function FirebaseAppProvider(props: React.PropsWithChildren<FirebaseAppProviderProps>) {
   const { firebaseConfig, appName, suspense } = props;
 
   const firebaseApp: FirebaseApp = React.useMemo(() => {
+    registerReactFireVersion();
+
     if (props.firebaseApp) {
       return props.firebaseApp;
     }
@@ -45,9 +45,6 @@ export function FirebaseAppProvider(props: React.PropsWithChildren<FirebaseAppPr
         throw new Error('No firebaseConfig provided');
       }
 
-      const reactVersion = React.version || 'unknown';
-      registerVersion('react', reactVersion);
-      registerVersion('reactfire', version);
       return initializeApp(firebaseConfig, appName);
     }
   }, [props.firebaseApp, firebaseConfig, appName]);