fix(code): clear import project input after submit (#32970)

Author: WangQianliang

x-pack/plugins/code/public/components/admin_page/import_project.tsx

@@ -46,6 +46,7 @@ class CodeImportProject extends React.PureComponent<
 
   public submitImportProject = () => {
     this.props.importRepo(this.state.value);
+    this.setState({ value: '' });
   };
 
   public render() {

x-pack/plugins/code/public/components/admin_page/project_tab.tsx

@@ -134,6 +134,7 @@ class CodeProjectTab extends React.PureComponent<Props, State> {
 
   public submitImportProject = () => {
     this.props.importRepo(this.state.repoURL);
+    this.setState({ repoURL: '' });
   };
 
   public renderImportModal = () => {