Shiny Updates: Trigger correct event after importer install

[swissspidy]

Currently, inside wp.updates.installImporterSuccess there is:

$document.trigger( 'wp-installer-install-success', response );

It should be:

$document.trigger( 'wp-importer-install-success', response );

[swissspidy]

In 37969:

Update/Install: Trigger the correct event after installing an importer plugin.

This fixes a typo inside wp.updates.installImporterSuccess() as it's about installing an importer, not an installer.

Fixes #37273.