Install WordPress Importer only when needed

[gamebits]

If the Custom Content Migrator is active and WordPress Importer is not installed and active, CCM will do so anytime any WP-CLI command is run. For example:

$ time wp search-replace //charlestoncitypaper-staging.newspackstaging.com //charlestoncitypaper.com --all-tables-with-prefix --report-changed-only --dry-run
Installing and activating the wordpress-importer plugin now...

newspack-custom-content-migrator/src/PluginSetup.php

Lines 70 to 72 in f6d99fb

	/**
	* Checks whether wordpress-importer is active and valid, and if not, installs and activates it.
	*/

It would be preferable if WordPress Importer were installed only when it is needed for the WP-CLI command being run.