WPCOM: Migrate wpcom.undocumented() site products to wpcom.req

[tyxla]

Changes proposed in this Pull Request

This PR migrates all the wpcom.undocumented() site products method to wpcom.req.get().

The PR also simplifies the code a little bit - we don't need to encode the site fragment, because anywhere in the code where we're making requests to this endpoint, we pass the numeric site ID. I think there was no reason to have support for anything else than a numeric site ID in the first place TBH (see #40306 and cc @DavidRothstein just in case). We're also removing an unnecessary wrapping Promise - wpcom.req.get() already returns a promise.

Part of the ongoing effort to get rid of wpcom.undocumented().

Testing instructions

• Go to /plans/:site where :site is one of your Jetpack sites.
• Verify that the request to /sites/:site/products is still successful.

[github-actions]

Link to Calypso live: https://calypso.live?image=registry.a8c.com/calypso/app:build-18752
Link to Jetpack Cloud live: https://calypso.live?image=registry.a8c.com/calypso/app:build-18752&env=jetpack

[jsnajdr]

👍

[jsnajdr]

It's nice that because siteId is always a number, we don't need to encodeURIComponent like the original method did.

[matticbot]

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

App Entrypoints (~19 bytes removed 📉 [gzipped])

name                   parsed_size           gzip_size
entry-main                  -182 B  (-0.0%)      -19 B  (-0.0%)
entry-login                 -182 B  (-0.0%)      -19 B  (-0.0%)
entry-gutenboarding         -182 B  (-0.0%)      -19 B  (-0.0%)
entry-domains-landing       -182 B  (-0.0%)      -19 B  (-0.0%)

Common code that is always downloaded and parsed every time the app is loaded, no matter which route is used.

Sections (~11 bytes removed 📉 [gzipped])

name                   parsed_size           gzip_size
plans                        -21 B  (-0.0%)      -11 B  (-0.0%)
jetpack-connect              -21 B  (-0.0%)      -11 B  (-0.0%)
jetpack-cloud-pricing        -21 B  (-0.0%)      -11 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.

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.

[DavidRothstein]

I think there was no reason to have support for anything else than a numeric site ID in the first place TBH (see #40306 and cc @DavidRothstein just in case)

I think the only reason I did it was to make this code an exact copy of the equivalent getSitePlans(). But since you're fixing that one in #57766 also, it seems fine to do it here too!