🐛 Fix Input.Password unmount crash (#18475)

close #18473

components/input/Password.tsx

@@ -55,7 +55,9 @@ export default class Password extends React.Component<PasswordProps, PasswordSta
   }
 
   saveInput = (instance: Input) => {
-    this.input = instance.input;
+    if (instance && instance.input) {
+      this.input = instance.input;
+    }
   };
 
   focus() {

components/input/__tests__/Password.test.js

@@ -61,4 +61,12 @@ describe('Input.Password', () => {
         .getDOMNode(),
     );
   });
+
+  // https://github.com/ant-design/ant-design/pull/18441
+  it('should unmount without error', () => {
+    const wrapper = mount(<Input.Password />);
+    expect(() => {
+      wrapper.unmount();
+    }).not.toThrow();
+  });
 });