Copy updates for Jetpack Scan

[scottsweb]

Changes proposed in this Pull Request

Refinements to copy in the Jetpack Scan UI. Remove odd break.

Before

After

Testing instructions

• npm run start-jetpack-cloud
• Check for updated copy in the Scan UI

[matticbot]

Test live: https://calypso.live/?branch=fix/copy-changes-jetpack-scan

[singerb]

@bhoop has some updates here too, but I think there's no PR yet? Can probably combine them.

[keoshi]

Left two small copy suggestions.

[matticbot]

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

Sections (~5 bytes removed 📉 [gzipped])

name  parsed_size           gzip_size
scan        +43 B  (+0.0%)       -5 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.

Fixes made

[scottsweb]

@singerb should be good for another review

[singerb]

Looks good to me, but as mentioned before I'll tag @bhoop in since he was working on some changes to the "we're here to help" wording I thought. Maybe in a different place though?

[scottsweb]

Superseded by #47416