test: Fix eg.initialSnapshot to use emailAddressVisibility override

I think we forgot this.
No callers in the tests currently use this override,
but it's probably a good idea to have it
properly overriding anyway.

Author: fombalang

test/example_data.dart

@@ -804,7 +804,7 @@ InitialSnapshot initialSnapshot({
     zulipMergeBase: zulipMergeBase ?? recentZulipVersion,
     alertWords: alertWords ?? ['klaxon'],
     customProfileFields: customProfileFields ?? [],
-    emailAddressVisibility: EmailAddressVisibility.everyone,
+    emailAddressVisibility: emailAddressVisibility ?? EmailAddressVisibility.everyone,
     serverTypingStartedExpiryPeriodMilliseconds:
       serverTypingStartedExpiryPeriodMilliseconds ?? 15000,
     serverTypingStoppedWaitPeriodMilliseconds: