Forms: Fix boot script timing with third-party plugins that use script modules

[lezama]

Resolves FORMS-667

Note upstream fix WordPress/gutenberg#76870

Description

The wp-build generated page-wp-admin.php attaches an import("@wordpress/boot") call to a classic inline script via wp_add_inline_script. In admin_print_footer_scripts, both _wp_footer_scripts (classic scripts) and print_import_map run at priority 10, but _wp_footer_scripts is registered first — so the inline import() executes before the import map is in the DOM.

This is a latent bug: bare specifier resolution requires the import map to already exist. It happens to work in most environments because browser microtask scheduling defers the actual resolution. But when a third-party plugin (e.g. The Events Calendar, via StellarWP) converts classic scripts to type="module" using script_loader_tag, the timing changes and @wordpress/boot fails to resolve — resulting in a blank Forms dashboard.

Fix

Move the import("@wordpress/boot") inline code from the classic script handle to a <script type="module"> printed at admin_print_footer_scripts priority 20, well after the import map (priority 10). Module scripts resolve bare specifiers using whatever import map is in the DOM at execution time, so the ordering is guaranteed.

The fix extracts the existing inline script verbatim — it doesn't reconstruct the boot config or depend on any @wordpress/boot internals.

The upstream fix is WordPress/gutenberg#76870.

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

No

Testing instructions:

1. Install and activate The Events Calendar
2. Navigate to Jetpack → Forms
3. Before: blank/dark page, console shows TypeError: Failed to resolve module specifier '@wordpress/boot'
4. After: dashboard loads normally
5. Deactivate The Events Calendar — Forms dashboard still works

[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 WoA dev 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 (Jetpack), and enable the fix/forms-boot-importmap-compat branch.
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[github-actions]

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Code Coverage Summary

Coverage changed in 1 file.

File	Coverage	Δ%	Δ Uncovered
projects/packages/forms/src/dashboard/class-dashboard.php	85/266 (31.95%)	-3.91%	29 💔

Full summary · PHP report · JS report

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