fix(gatsby-plugin-netlify): Do not cache static query data

[ksmithbaylor]

Description

I recently ran into some strange issues on my site that boiled down to queries that came from useStaticQuery being immutably cached. The underlying data fetched by the static queries had changed after a redeploy, but when the page loaded in browsers with a warm cache, the relevant components showed the stale data after a brief flash of the new data from the HTML (before JS had loaded).

Since static queries are given a deterministic query hash based on the query itself (not the query results) and written to /static/d/{queryHash}.json, the resulting file is cached indefinitely per the /static/* caching header.

This PR gives these files the same cache headers as the page-data.json files generated by Gatsby, since their purpose is similar.

[KyleAMathews]

1. very sorry about this bug
2. excellent job debugging it!
3. really appreciate you jumping in with a fix!
4. @sidharthachatterjee already fixed the underlying issue by moving static queries to be written to the same directly as page queries so the existing caching rules people use keep working fix(gatsby): Move static queries to page data dir #26242

Cheers!

[ksmithbaylor]

Perfect, thanks @KyleAMathews! I hadn't seen that update yet, sounds like it will fix my problem in a cleaner way.