Settings: Improved load times by reducing number of XHRs

[seanmonstar]

┆Issue is synchronized with this Jira Task
┆Issue Number: FXA-776

[shane-tomlinson]

Ref #3374

[clouserw]

We should add the settings page to https://sql.telemetry.mozilla.org/dashboard/fxa-performance to get some hard numbers and see how it compares to the rest of the site

[philbooth]

We should add the settings page

So numbers from settings do make it into that dashboard, it's just that we didn't spend time distinguishing them yet. At the time, our main concern was performance of the signin/signup views as they impact our funnels, and those views are labelled as auth in the charts.

The categorisation of events from those views happens here:

fxa/packages/fxa-content-server/server/lib/flow-event.js

Line 74 in 098fe07

const AUTH_VIEWS = new Set(['enter-email', 'force-auth', 'signin', 'signup']);

...and then later:

fxa/packages/fxa-content-server/server/lib/flow-event.js

Lines 85 to 87 in 098fe07

	const performanceCategory = AUTH_VIEWS.has(metrics.initialView)
	? 'auth'
	: 'other';

We could do something similar to pull settings data out of the other bucket. Or maybe it's better to segment all the data by view name, and get rid of that categorisation which was kind of a hack anyway. We can easily combine view names in the queries if we want to categorise auth/other.

[shane-tomlinson]

ref #862, #2561