AddNewTabUseCase calls loadUrl twice

[csadilek]

This happens for initial page loads if an engine session needs to still be linked. Then we load the URL once while linking and once right after via the call loadUrl:

https://github.com/mozilla-mobile/android-components/blob/master/components/feature/tabs/src/main/java/mozilla/components/feature/tabs/TabsUseCases.kt#L129

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