Fix bug on PL events without events property

[martindale]

Ran into this while working on a bridge of my own, thanks to @david:vovo.id.au in the Matrix Bridging room for confirming.

[Half-Shot]

Thanks for the contrib, would you mind signing off as per https://github.com/matrix-org/synapse/blob/master/CONTRIBUTING.md ?

[jaller94]

This became obsolete by #185.

The new lines are:

matrix-appservice-bridge/src/components/intent.ts

Lines 780 to 786 in 7df1372

	const requiredLevel = returnFirstNumber(
	// If these are invalid or not provided, default to 0 according to the Spec.
	// https://matrix.org/docs/spec/client_server/r0.6.0#m-room-power-levels
	(event.content.events && event.content.events[eventType]),
	defaultLevel,
	0
	);

My solution even accounts for default_state being undefined or any of these not being numbers.