Datepicker: When selecting a month in a year/month mode, the day selection flashes on click

#### Reproduction

https://stackblitz.com/angular/kgvngvkblme?file=src%2Fapp%2Fdatepicker-views-selection-example.ts

Steps to reproduce:
1. Click on the calendar icon
2. Select a year
3. Select a month

This is actually the example from https://material.angular.io/components/datepicker/overview, although I found it more noticeable in my app

#### Expected Behavior

The datepicker calendar should close immediately.

#### Actual Behavior

When clicked on the month, the calendar briefly switches into monthly view (therefore displaying all the weeks and days), before closing.

#### Environment

- Angular: 10.2.0
- CDK/Material: 10.2.5
- Browser(s): Chrome
- Operating System (e.g. Windows, macOS, Ubuntu): macOS

从 StackBlitz 复现开始，尤其是 src/app/datepicker-views-selection-example.ts，并在 Angular datepicker 中复现先选择年份再选择月份的操作。跟踪选择月份后的过渡过程，并确认日视图不会短暂显示，日历会立即关闭。

由索引模型根据 Issue 内容生成。