bug(cdkTextareaAutosize): Textarea does not size to fit with initial value until window is resized

### 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

Auto resize of the cdkTextareaAutosize directive for a textarea, which has an initial value bound to it, is not working.

### Reproduction

It is a fork of the "Auto-resizing textarea" example of https://material.angular.io/cdk/text-field/overview. I have just added ngModel with a initial value of 5 lines. This 5 lines should be displayed without scrolling (cdkAutosizeMaxRows is also set to 5).
StackBlitz link: https://stackblitz.com/edit/oktcnmdj
Steps to reproduce:
1. Start example

### Expected Behavior

Textarea should immediatly show all 5 lines without scrollbar, without resizing the window.

### Actual Behavior

Scrollbar is shown and only 3 lines are displayed
After resizing the window it works.

### Environment

- Angular: 19.2.3
- CDK/Material: 19.2.3
- Browser(s): chrome 134.0.6998.89
- Operating System (e.g. Windows, macOS, Ubuntu): Windows 11

首先运行链接的 StackBlitz 复现，并检查 cdkTextareaAutosize 指令在具有初始 ngModel 值且 cdkAutosizeMaxRows 设置为 5 时的行为。确认无需调整窗口大小即可显示全部五行，并且不会出现滚动条，这与 issue 中描述的预期行为一致。

由索引模型根据 Issue 内容生成。