bug(MatList): Icons do not respect RTL direction

### 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 using MatList in an RTL project, the icons do not adjust their margins correctly based on the text direction (dir="rtl"). The left and right margins remain the same as in LTR mode, causing misalignment in RTL layouts.

I was able to fix this issue easily with custom CSS, but I wanted to report it as a bug in case it needs to be addressed in the library.

### Reproduction

StackBlitz link:
Steps to reproduce:
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### Expected Behavior

Icons should switch their margins correctly when dir="rtl" is set.

### Actual Behavior

Icons remain aligned as if the project is LTR, leading to incorrect spacing.

### Environment

Angular: 18
Angular Material: 19.1.5
Browser: Latest version of Chrome
Operating System: Windows (running a Linux dev container on WSL)

まず、dir="rtl" と最新の Chrome を使用し、Angular Material 19.1.5 を使った Angular 18 プロジェクトで MatList のアイコン間隔の問題を再現します。RTL と LTR におけるアイコンのマージンと配置を比較します。アイコンの間隔がテキストの方向に正しく従えば、issue は完了です。

索引モデルが issue の本文から書いたものです。