bug(Button & Table): Button inside table with sticky column overlaps

### 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

Hello,

When placing a mat-button inside a table cell, it appears above the sticky columns instead of being clipped or hidden like the rest:

https://github.com/user-attachments/assets/dd355abc-e352-4db7-8a7c-7bdea2d7dfb3

This issue is reproducible with:
- Angular Material 15: https://stackblitz.com/edit/3p4mdjwq?file=src%2Fapp%2Ftable-sticky-columns-example.html
- Angular Material 19: https://stackblitz.com/edit/dcghq85p?file=src%2Fexample%2Ftable-sticky-columns-example.html,src%2Fexample%2Ftable-sticky-columns-example.ts,package.json

I haven't tested with other versions.

Thanks!

### Reproduction

StackBlitz link: https://stackblitz.com/edit/dcghq85p?file=src%2Fexample%2Ftable-sticky-columns-example.html,src%2Fexample%2Ftable-sticky-columns-example.ts,package.json
Steps to reproduce:
1. Scroll horizontally

### Expected Behavior

The button should be hidden when scrolled out the visible area.

### Actual Behavior

The button appears above the sticky columns.

### Environment

- Angular: 19
- CDK/Material: 19
- Browser(s): Firefox
- Operating System (e.g. Windows, macOS, Ubuntu): Windows

Angular Material 19 の StackBlitz reproduction から始め、特に src/example/table-sticky-columns-example.html と src/example/table-sticky-columns-example.ts を確認します。Firefox で実行して横方向にスクロールし、sticky column 上の button を観察します；button が表示されている table area から外れたときに非表示になれば完了です。

索引モデルが issue の本文から書いたものです。