Editing templates with [candidate_dashboard] shortcode

This message isn’t in a template file.

if ( ! is_user_logged_in() ) {
			_e( 'You need to be signed in to view this page.', 'wp-job-manager-resumes' );
			return;
		}

You can customise the message easily using https://www.ads-software.com/plugins/say-what/ if you want to do that.

Not sure if i did this the right way but i had to edit “class-wp-resume-manager-shortcodes.php”

Editing will mean you lose your changes during updates. The plugin method I posted would make it upgrade safe.