fix(analytics): invoke ValoraAnalytics.init correctly (#3823)

### Description

`this` object was not bound correctly causing analytics events to not
fire since #3672 which went in
on 1.57.0

### Test plan

Manually, by enabling analytics on dev build

Before, ValoraAnalytics.track was bailing here
https://github.com/valora-inc/wallet/blob/ffb97d37a158a78b61dd4a507b3d7dad5b168fa5/src/analytics/ValoraAnalytics.ts#L249-L252

After the fix, confirmed with logs that events are successfully sent to
segment

### Related issues

N/A

### Backwards compatibility

N/A

src/app/saga.ts

@@ -131,7 +131,7 @@ export function* appInit() {
 
   yield all([
     call(initializeSentry),
-    call(ValoraAnalytics.init),
+    call([ValoraAnalytics, 'init']),
     call(
       initI18n,
       language || bestLanguage || DEFAULT_APP_LANGUAGE,