core(responsiveness): use raw trace event

[brendankenny]

part of #13916

Rather than the responsiveness computed artifact returning just the duration, it now returns the whole trace event, which will allow the attribution audit to use all the other properties on that same event.

Functionality is unchanged.

[brendankenny]

kind of harkens back to your trace types, @connorjclark :)

I kind of like this pattern of building up the event type compared to the Omit<>+build pattern used here:

lighthouse/lighthouse-core/lib/tracehouse/trace-processor.js

Lines 21 to 23 in 0fcf4a7

	/** @typedef {Omit<LH.TraceEvent, 'name'|'args'> & {name: 'FrameCommittedInBrowser', args: {data: {frame: string, url: string, parent?: string}}}} FrameCommittedEvent */
	/** @typedef {Omit<LH.TraceEvent, 'name'|'args'> & {name: 'largestContentfulPaint::Invalidate'|'largestContentfulPaint::Candidate', args: {data?: {size?: number}, frame: string}}} LCPEvent */
	/** @typedef {Omit<LH.TraceEvent, 'name'|'args'> & {name: 'largestContentfulPaint::Candidate', args: {data: {size: number}, frame: string}}} LCPCandidateEvent */

(where you still have some random optional properties from the LH.TraceEvent frankenstein)

[connorjclark]

nit: did you consider defining this in .d.ts (for ergonomic reasons)?

[brendankenny]

nit: did you consider defining this in .d.ts (for ergonomic reasons)?

maybe if it spreads, but so far it's really just needed in this one file and the two files that call it are fine with the implicit type from the function return.

There's also the multi-line jsdoc format, it's just unfortunate that vscode doesn't do better syntax highlighting for it (probably should file that as an issue at some point).