refactor: [migration] convert iframe chart into dashboard markdown component (#10590)

* refactor: [migration] convert iframe chart into dashboard markdown component

* remove 3 viz_types

* fix comments

superset-frontend/src/explore/components/SaveModal.jsx

@@ -33,8 +33,6 @@ import { CreatableSelect } from 'src/components/Select/SupersetStyledSelect';
 import { t } from '@superset-ui/translation';
 import ReactMarkdown from 'react-markdown';
 
-import { EXPLORE_ONLY_VIZ_TYPE } from '../constants';
-
 const propTypes = {
   can_overwrite: PropTypes.bool,
   onHide: PropTypes.func.isRequired,
@@ -134,8 +132,6 @@ class SaveModal extends React.Component {
     this.setState({ alert: null });
   }
   render() {
-    const canNotSaveToDash =
-      EXPLORE_ONLY_VIZ_TYPE.indexOf(this.state.vizType) > -1;
     return (
       <Modal show onHide={this.props.onHide}>
         <Modal.Header closeButton>
@@ -225,9 +221,7 @@ class SaveModal extends React.Component {
               id="btn_modal_save_goto_dash"
               bsSize="sm"
               disabled={
-                canNotSaveToDash ||
-                !this.state.newSliceName ||
-                !this.state.newDashboardName
+                !this.state.newSliceName || !this.state.newDashboardName
               }
               onClick={this.saveOrOverwrite.bind(this, true)}
             >

superset-frontend/src/explore/components/controls/VizTypeControl.jsx

@@ -74,7 +74,6 @@ const DEFAULT_ORDER = [
   'line_multi',
   'treemap',
   'box_plot',
-  'separator',
   'sunburst',
   'sankey',
   'word_cloud',
@@ -85,7 +84,6 @@ const DEFAULT_ORDER = [
   'bubble',
   'deck_geojson',
   'horizon',
-  'markup',
   'deck_multi',
   'compare',
   'partition',
@@ -95,7 +93,6 @@ const DEFAULT_ORDER = [
   'world_map',
   'paired_ttest',
   'para',
-  'iframe',
   'country_map',
 ];