Don't use WP_CLI::error() when installing translations for multiple locales

[ocean90]

This is about

language-command/src/Plugin_Language_Command.php

Lines 212 to 225 in f71622d

	foreach ( $language_codes as $language_code ) {
	if ( in_array( $language_code, $available, true ) ) {
	\WP_CLI::warning( "Language '{$language_code}' already installed." );
	} else {
	$response = $this->download_language_pack( $language_code, $plugin );
	if ( is_wp_error( $response ) ) {
	\WP_CLI::error( $response );
	} else {
	\WP_CLI::success( 'Language installed.' );
	}
	}
	}

Example command: wp language plugin install <plugin-name> de_DE de_CH
When the installation of de_DE fails the command should continue to install de_CH. The failed installation should be documented as warning.
This would be similar to the media regenerate command which uses Utils\report_batch_operation_results().

[schlessera]

Yes, seems that this would be more consistent to what other similar commands are doing.

Are you up for providing a PR for this?

[ocean90]

Started in #63.

[ocean90]

If #63 looks good we should probably do the same for the uninstall commands.