jetpack-mu-wpcom: Stabilize build

[anomiex]

Proposed changes:

PR #38093 added downloading of translation data into the build for the package, and decided to store the current date in each file meaning that every file changes for every single build. This clutters up the history of the mirror repo, making it hard to see what the actual changes are since every trunk commit has these useless date changes.

We can improve the situation somewhat by saving the HTTP Last-Modified date into the files instead of the current date, so they should only be updated when the translations actually change. We'll still get updates attributed to whichever unrelated trunk commit happened to be the next after a change on the translation server, but at least we won't get it for every single commit.

Even better, IMO, would be if the translations could be downloaded to sites as needed like WordPress does with translations for plugins installed from wporg. But that would probably require a lot more refactoring.

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

None. But have a look at https://github.com/Automattic/jetpack-mu-wpcom-plugin/commits/trunk/vendor/automattic/jetpack-mu-wpcom/src/features/help-center/languages

Does this pull request change what data or activity we track or use?

No

Testing instructions:

• Is the build happy?
• Check the dates in the files.

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WordPress.com Simple site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin, and enable the fix/constant-changes-for-help-center-languages branch.

  • For jetpack-mu-wpcom changes, also add define( 'JETPACK_MU_WPCOM_LOAD_VIA_BETA_PLUGIN', true ); to your wp-config.php file.

• To test on Simple, run the following command on your sandbox:

  bin/jetpack-downloader test jetpack-mu-wpcom-plugin fix/constant-changes-for-help-center-languages
  

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

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[alshakero]

Thank you for this. Lesson learned.

It's crazy that I got a shower idea 10 minutes ago, and I realized I can remove a lot of this complexity if I made translation files JS files and enqueued them using their URL instead. I'll send a PR soon.