calypso_new_user_site_creation: Add more tracking props

[escapemanuele]

This PR simply adds a couple more props to the calypso_new_user_site_creation event.

This could help in determining differences in the Start/Stepper experiment.

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-122077

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-122077&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-122077&env=a8c-for-agencies

[matticbot]

Here is how your PR affects size of JS and CSS bundles shipped to the user's browser:

Sections (~259 bytes added 📈 [gzipped])

name                           parsed_size           gzip_size
write-flow                           +76 B  (+0.0%)      +17 B  (+0.0%)
videopress-tv-flow                   +76 B  (+0.1%)      +24 B  (+0.1%)
videopress-flow                      +76 B  (+0.0%)      +19 B  (+0.0%)
transferring-hosted-site-flow        +76 B  (+0.1%)      +24 B  (+0.1%)
signup                               +76 B  (+0.0%)      +24 B  (+0.0%)
sensei-flow                          +76 B  (+0.0%)      +24 B  (+0.0%)
plugin-bundle-flow                   +76 B  (+0.0%)      +23 B  (+0.0%)
link-in-bio-tld-flow                 +76 B  (+0.0%)      +21 B  (+0.0%)
import-hosted-site-flow              +76 B  (+0.0%)      +23 B  (+0.0%)
copy-site-flow                       +76 B  (+0.0%)      +29 B  (+0.0%)
build-flow                           +76 B  (+0.0%)      +25 B  (+0.0%)
update-design-flow                   +61 B  (+0.0%)      +18 B  (+0.0%)
onboarding-flow                      +61 B  (+0.3%)      +15 B  (+0.2%)
jetpack-connect                      +61 B  (+0.0%)      +18 B  (+0.0%)
accept-invite                        +61 B  (+0.0%)      +18 B  (+0.0%)

Sections contain code specific for a given set of routes. Is downloaded and parsed only when a particular route is navigated to.

Async-loaded Components (~17 bytes added 📈 [gzipped])

name                                     parsed_size           gzip_size
async-load-calypso-lib-analytics-signup        +61 B  (+0.5%)      +17 B  (+0.4%)

React components that are loaded lazily, when a certain part of UI is displayed for the first time.

Legend

What is parsed and gzip size?

Parsed Size: Uncompressed size of the JS and CSS files. This much code needs to be parsed and stored in memory.
Gzip Size: Compressed size of the JS and CSS files. This much data needs to be downloaded over network.

Generated by performance advisor bot at iscalypsofastyet.com.

[matticbot]

This PR modifies the release build for the following Calypso Apps:

For info about this notification, see here: PCYsg-OT6-p2

• blaze-dashboard
• odyssey-stats

To test WordPress.com changes, run install-plugin.sh $pluginSlug improve-signup-complete-tracking on your sandbox.