Modify Filter to cause a field to be not Required

Working with a Simple Job Board Plug in the is requiring the user to upload a resume. I have very simple needs and do not need to have the resume attached (but would like to leave it as optional)

I have narrowed the code down to the line:
apply_filters('sjb_resume_required', 'required="required"')

But I am unsure how to "turn it off.
Any guidance would be appreciated.
Below is a bit more of the code before and after..


$sjb_attach_resume = '<div class="form-group">'
                    . '<label for="applicant_resume">' . apply_filters('sjb_resume_label', __('Attach Resume', 'simple-job-board')) . '<span class="sjb-required required">*</span></label>'
                    . '<input type="file" name="applicant_resume" id="applicant-resume" class="sjb-attachment form-control "' . apply_filters('sjb_resume_required', 'required="required"') . '>'
                    . '<span class="sjb-invalid-attachment validity-note" id="file-error-message"></span>'
                    . '</div>';
            echo apply_filters('sjb_attach_resume', $sjb_attach_resume);