[Theme] Reduce max batch bytesize to reduce 502 errors

[frandiox]

WHY are these changes introduced?

Fixes #5247

TODO:

• Reduce size only for themekit access, or
• Reduce the size after getting the first 502 error (i.e. try without restrictions first, then make the batches smaller if it fails)

WHAT is this pull request doing?

Reduce max batch bytesize for uploads temporarily.

How to test your changes?

Post-release steps

Measuring impact

How do we know this change was effective? Please choose one:

• n/a - this doesn't need measurement, e.g. a linting rule or a bug-fix
• Existing analytics will cater for this addition
• PR includes analytics changes to measure impact

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes

[frandiox]

/snapit

[github-actions]

🫰✨ Thanks @frandiox! Your snapshot has been published to npm.

Test the snapshot by installing your package globally:

pnpm i -g @shopify/[email protected]

After installing, validate the version by running just shopify in your terminal
If the versions don't match, you might have multiple global instances installed.
Use which shopify to find out which one you are running and uninstall it.

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟡	Statements	75.61% (+0.01% 🔼)	9053/11974
🟡	Branches	70.86% (+0.02% 🔼)	4416/6232
🟡	Functions	75.4%	2375/3150
🟡	Lines	76.12% (+0.02% 🔼)	8549/11231

Show files with reduced coverage 🔻

St.❔	File	Statements	Branches	Functions	Lines
🟢	... / app-event-watcher.ts	95.18% (-1.2% 🔻)	86.49% (-2.7% 🔻)	95.45%	100%

Test suite run success

2044 tests passing in 913 suites.

Report generated by 🧪jest coverage report action from 2b69b1f