Force downgrade if any stream has downgraded to standard OTLP

[jmacd]

Is your feature request related to a problem? Please describe. Request statement: https://github.com/open-telemetry/oteps/pull/171/files/8e65c10c78dc44fea72b47b272282979943f9d3d#r1071566034

Describe the solution you'd like Signal the healthy streams when downgrade occurs for them to also downgrade, so that exporter behavior is consistent across data items (at least).