fix(gatsby): handle case of html and data files mismatch

[pieh]

Description

If for whatever reason html content from old deploys gets loaded (some cases of browser cache), that old html will load old .js bundles. The page-data and app-data files will however be fetched for newest deploy. If there was webpack recompilation happening between those deploys issues might appear - such as js bundle expecting some static queries to be loaded by our loader, but they never do because new page-data files have different set of static queries to fetch. All of this can result in dreadful "The result of this StaticQuery could not be fetched" errors (when using useStaticQuery hook) or "Loading (StaticQuery)" placeholder text (for <StaticQuery> component).

Potential solution (implemented in this PR):

• inline webpackCompilationHash in every html page
• use that and compare it to hash from just fetched app-data.json file
• if they don't match it should mean that our data files (such as app-data.json and page-data.json) were from different build and they might not be compatible. In that case try to reload (with extra step of checking if we just reloaded already to avoid infinite reload loop - if refresh didn't fix mismatch, then likely deploy in current shape is borked, so no point in trying it again and again)

Related Issues

Related to #33956

[KyleAMathews]

I like this a lot. This would handle both hosts that don't force validation on html files + service worker issues. Nice work!

[aaronadamsCA]

I think this may solve #33112 as well.

[DSchau]

@aaronadamsCA let us know if it does! Would be great to validate that hypothesis.

[aaronadamsCA]

Might need to resolve #34484 before getting a read on this.