ExpandableSection - move placement of icon pf-m-expand-top modifier class

Describe the enhancement or change
https://github.com/patternfly/patternfly-react/pull/11851 notes a TODO to move the placement of the pf-m-expand-top modifier class. This needs to be removed from the expandableSectionToggleIcon element to the outermost ExpandableSection

Is this request originating from a Red Hat product team? If so, which ones and is there any sort of deadline for this enhancement?

Any other information?

首先定位 ExpandableSection 组件及其 expandableSectionToggleIcon 元素，然后阅读 pull request #11851 中的 TODO 和相关上下文。将 pf-m-expand-top modifier class 移动到最外层的 ExpandableSection，并验证渲染后的类的位置以及组件现有行为是否正确。