childLabelProp vs elementLabelProp

### Describe the bug

Within the code base we use both, `elementLabelProp` and `childLabelProp` as the UI Schema option to define a label for array elements.

### Expected behavior

This is not intended and should be aligned. For a backward compatible solution we should probably support both options, with `elementLabelProp` taking higher precedence as it's the intended option.

### Steps to reproduce the issue

Try to use `elementLabelProp` and/or `childLabelProp` with the React Material and the Vue renderer sets.

### Screenshots

_No response_

### In which browser are you experiencing the issue?

N/A

### Framework

React, Vue 3, Vue 2

### RendererSet

Material, Vanilla

### Additional context

See:
- https://github.com/eclipsesource/jsonforms-vuetify-renderers/issues/45
- https://jsonforms.discourse.group/t/labels-for-array-of-strings/707/4