Material labels should be vertically centered in their grid cell

**Describe the bug**
When using material react renderers, labels are aligned at the top inside their grid cell.
Combining this behavior with horizontal layouts leads to labels being shown too high.

**To Reproduce**
Steps to reproduce the behavior:
1. Have a `Label` and a `Control` next to each other inside a `HorizontalLayout`
2. The label looks to be places too high

**Expected behavior**
The label is centered in the row created by the horizontal layout.

**Screenshots**

**Browser (please complete the following information):**
Tested with Chrome and Firefox (should be browser independent)

**Used Setup (please complete the following information):**
- Framework: react
- RendererSet: material