Fix: Replace deprecated wp.updates.l10n.updating with wp.i18n.__

[manishdhorepatil-art]

Fixes a deprecated JavaScript usage in the WordPress admin.

The code in wp-admin/js/theme.js was using wp.updates.l10n.updating, which has been deprecated since WordPress 5.5. This PR replaces it with the recommended wp.i18n.__() function.

Testing Instructions

Go to Dashboard → Updates or Appearance → Themes

Trigger a theme update

Confirm:

The text “Updating...” appears correctly

No deprecation notice appears in the browser console

Trac Ticket

Fixes: https://core.trac.wordpress.org/ticket/64619

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Props manishxdp, westonruter.

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[westonruter]

I see there are quite a few reads of the l10n object as well. Should those not be updated as well?

[westonruter]

There is a seeming duplicate PR opened at the same time: #10895. Should this be close in favor of that, or the other way around?

[manishdhorepatil-art]

Thanks for the review, @westonruter.
I checked theme.js and found that line 1280 already uses wp.i18n.__('Updating...') instead of wp.updates.l10n.updating. I didn't find other direct references to wp.updates.l10n in this file.
Could you point to the specific instances you're seeing? I can:
Check other files if they're outside theme.js

[westonruter]

Here:

wordpress-develop/src/js/_enqueues/wp/theme.js

Line 122 in f9275df

.append( $.parseHTML( '<label for="wp-filter-search-input">' + l10n.search + '</label>' ) )

wordpress-develop/src/js/_enqueues/wp/theme.js

Lines 976 to 978 in f9275df

	$button.attr({ 'aria-expanded': 'false', 'aria-label': l10n.expandSidebar });
	} else {
	$button.attr({ 'aria-expanded': 'true', 'aria-label': l10n.collapseSidebar });

And so on.

[manishdhorepatil-art]

@westonruter Could you please checknow added nessary changes