Add font settings to the submit block

[MAILPOET-2911]

assets/js/src/form_editor/blocks/submit/edit.tsx

@@ -68,6 +68,10 @@ const SubmitEdit = ({ attributes, setAttributes }) => {
     styles.backgroundColor = attributes.styles.backgroundColor;
   }
 
+  if (attributes.styles.fontFamily && !attributes.styles.inheritFromTheme) {
+    styles.fontFamily = attributes.styles.fontFamily;
+  }
+
   const className = classnames('mailpoet_submit', { button: attributes.styles.inheritFromTheme });
 
   return (

assets/js/src/form_editor/blocks/submit/styles_settings.tsx

@@ -11,6 +11,7 @@ import { partial } from 'lodash';
 import ColorSettings from 'form_editor/components/color_settings';
 import FontSizeSetting from 'form_editor/components/font_size_settings';
 import { FormSettingsType } from 'form_editor/components/form_settings/form_settings';
+import FontFamilySettings from '../../components/font_family_settings';
 
 type Styles = {
   fullWidth: boolean,
@@ -19,6 +20,7 @@ type Styles = {
   backgroundColor?: string,
   fontColor?: string,
   fontSize?: number,
+  fontFamily?: string,
   borderSize?: number,
   borderRadius?: number,
   borderColor?: string,
@@ -103,6 +105,11 @@ const StylesSettings = ({
                 onChange={partial(updateStyles, 'bold')}
                 className="mailpoet-automation-styles-bold-toggle"
               />
+              <FontFamilySettings
+                name={MailPoet.I18n.t('formSettingsStylesFontFamily')}
+                value={styles.fontFamily || formSettings.fontFamily}
+                onChange={partial(updateStyles, 'fontFamily')}
+              />
               <RangeControl
                 label={MailPoet.I18n.t('formSettingsInputPadding')}
                 value={