[Feature]: implement `encoding` support in OTLPHttpExporter

### Component

Config

### Problem Statement

The exporter currently does not support configuring the `encoding` property, this is required by the schema.

### Proposed Solution

Set the encoding option on the exporter using the `Encoding` property on the parsed configuration. 

### Alternatives

_No response_

### Prior Art

_No response_

### Additional Context

_No response_