WordPress: Redirect the Plugins and Plugins > Add New pages to the WP Admin Dashboard.

functions.php

<?php

/**
 * WP Admin Page Redirects.
 *
 * Redirect the Plugins and Plugins > Add New pages to the WP Admin Dashboard in
 * order to prevent the installation of plugins for overzealous editors.
 *
 * @since 1.0.0
 *
 * @param object|null $my_current_screen Get the current screen object
 */
add_action(
	'current_screen',
	function() {
		$my_current_screen = get_current_screen();

		if ( isset( $my_current_screen->base ) && 'plugin-install' || 'plugins' === $my_current_screen->base ) {
			wp_safe_redirect( admin_url() );
			exit();
		}
	}
);