[ReactPoll] Fixed unintended behavior in rpollset embed

[trumoose]

In the current branch, .rpollset embed doesn't behave correctly when no votes are received -- it also sends in two separate messages with the question and NO ONE VOTED message: one that obeys the current rpollset embed setting, and one that doesn't. (see below for examples.)

To rectify this, the code block responsible has been greatly simplified, and sending the message happens in one place at the end of the method instead of at the middle and at the end. I'm welcome to suggestions for formatting changes, but the logic itself should be sound.

CURRENT BRANCH BEHAVIOR:

• Ending a poll in current branch with no votes (rpollset embed on):

• Ending a poll in current branch with no votes (rpollset embed off):

PR BRANCH BEHAVIOR:

• Ending a poll in PR branch with no votes (rpollset embed on):

• Ending a poll in PR branch with no votes (rpollset embed off):

[aikaterna]

The issue could have been fixed by just adding a "not" on line 225, if self.embed: -> if not self.embed:, but your changes condensed the 3 message sends into one message, and I agree with that change.