Fix bug where onPlayerError method was not called

[ElenaVielva]

Javascript method onPlayerError was not called, therefore, no errors are forwarded to the app. To get the player errors, we need to either change the initializer to map the events to the js methods or a rename of the current one. I opted for the second option. Reference

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[ElenaVielva]

@googlebot I signed it!

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[ElenaVielva]

@googlebot I fixed it.

[brol1dev]

@ElenaVielva I saw that you signed the CLA. Thanks for that. A couple of things:

• We need to confirm if this was really an issue. A question I have is why is it only a problem with the error callback and not other events? From what I see they all follow the same pattern, so it's odd that just renaming the method fixed the issue.
• could you resolve the new conflicts of your PR?

Thank you!