bug(datepicker): Date range picker emit repeated events after the first date is selected

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

When a date range picker is opened and the start date is selected, two consecutive valueChanges event are triggered, and after the end date is selected the final event is triggered, in total 3 events happens instead of only two.

Reproduction

StackBlitz link: https://stackblitz.com/edit/shrtut?
Steps to reproduce:

1. Click on the mat-datepicker-toggle button.
2. Select a start date like: 6/18/2023
3. Notice on the Changes section below that two events were triggered.
4. Select the end date: 6/24/2023.
5. A final event in logged on the Changes section.

Expected Behavior

After selecting the first date only a single valueChanges event should be triggered.

The expected behavior is show on the Workaround Changes section where a debounceTime(0) is forced in order to remove the spurious repeated event.

Actual Behavior

Two events are triggered after selecting the start date

Environment

• Angular: 16.1.1
• CDK/Material: 16.1.1
• Browser(s): Firefox, Chrome.
• Operating System: Linux (Fedora)

从链接的 StackBlitz 复现开始，并使用 mat-datepicker-toggle 和 valueChanges 测试 Angular Material date range picker 流程。在 Changes 部分复现先选择 6/18/2023、再选择 6/24/2023，然后将其与 debounceTime(0) 这一变通方案进行比较。完成的标准是：开始日期之后有一次 valueChanges 事件，结束日期之后也有一次。