Fix test flake.

[samwho]

Description

We've had a flake that's caused by an attempt to store JSON inside of a CSV by replacing the double quotes with single quotes, e.g.

"{ 'hello': 'world' }"

Which works great, until you want to store a value with a real single quote in it:

"{ 'hello': 'world's' }"

Because now when we try to parse that by switching the single quotes back out for double quotes, we get invalid JSON:

{ "hello": "world"s" }

I've fixed this by doing proper CSV double-quote escaping on the encoded JSON string.

[qa-wolf]

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