bug(button): Icons inside mat-button inside ng-template no longer vertically aligned

[alienwareone]

Is this a regression?

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

The previous version in which this bug was not present was

14.x

Description

Regression between legacy implementation and new MDC implementation.

Reproduction

Correct vertical alignment with legacy implementation: https://stackblitz.com/edit/angular-yetsx8?file=src%2Fapp%2Fbutton-overview-example.html

Incorrect vertical alignment with MDC implementation: https://stackblitz.com/edit/angular-hr8fqg?file=src%2Fapp%2Fbutton-overview-example.html

Expected Behavior

1. the alignment behavior should be unchanged, or
2. the change in behavior should be documented in the changelog

Actual Behavior

The aligment is different and this is not mentioned in the changelog or migration guide.

Environment

Angular: 15.0.0 CDK/Material: 15.0.0 Browser(s): Chrome Operating System (e.g. Windows, macOS, Ubuntu): Windows