Fix scrolling issues when closing some dropdown menus (#14606)

app/javascript/mastodon/components/dropdown_menu.js

@@ -205,7 +205,7 @@ export default class Dropdown extends React.PureComponent {
 
   handleClose = () => {
     if (this.activeElement) {
-      this.activeElement.focus();
+      this.activeElement.focus({ preventScroll: true });
       this.activeElement = null;
     }
     this.props.onClose(this.state.id);

app/javascript/mastodon/features/compose/components/privacy_dropdown.js

@@ -179,7 +179,7 @@ class PrivacyDropdown extends React.PureComponent {
     } else {
       const { top } = target.getBoundingClientRect();
       if (this.state.open && this.activeElement) {
-        this.activeElement.focus();
+        this.activeElement.focus({ preventScroll: true });
       }
       this.setState({ placement: top * 2 < innerHeight ? 'bottom' : 'top' });
       this.setState({ open: !this.state.open });
@@ -220,7 +220,7 @@ class PrivacyDropdown extends React.PureComponent {
 
   handleClose = () => {
     if (this.state.open && this.activeElement) {
-      this.activeElement.focus();
+      this.activeElement.focus({ preventScroll: true });
     }
     this.setState({ open: false });
   }