fix(material): adjust empty value for number/bool type (#1538)
fix(material): adjust empty value for number/bool type (#1538)


formly-js/ng-formly,ngx-formly/ngx-formly,formly-js/ng2-formly,ngx-formly/ngx-formly,formly-js/ng2-formly,formly-js/ng2-formly,ngx-formly/ngx-formly,ngx-formly/ngx-formly,formly-js/ng-formly