[Bug]: Open Telemetry is configured when environment variables are blank

[antdking]

What happened?

When starting the server with chroma run /config.yaml, Open Telemetry exporting is started if the following environment variables are set to blank values:

CHROMA_OPEN_TELEMETRY__ENDPOINT=""
CHROMA_OPEN_TELEMETRY__SERVICE_NAME=""

With the endpoint being blank, the following error occurs:

server-1  | thread 'main' panicked at rust/tracing/src/init_tracer.rs:69:10:
server-1  | could not build span exporter for tracing: ExportFailed(InvalidUri(InvalidUri(Empty)))
server-1  | note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

We'd expect that the variables being blank starts with open telemetry disabled the same way as if the variables are unset:

server-1  | OpenTelemetry is not enabled because it is missing from the config.
server-1  | Listening on 0.0.0.0:8000

Versions

Chroma v1.0.10

Relevant log output

[tazarov]

@antdking, I've added a small fix to address the empty address. The "side effect" is that you'll get tracing (aka logs) messages in console when empty OTEL endpoint is provided.