Add opentelemetry-exporter-otlp dependency

[IvanVan]

opentelemetry-exporter-otlp was removed in this PR #59, because dependency checker reported error:

[WARNING] Unused declared dependencies found:
[WARNING]    io.opentelemetry:opentelemetry-exporter-otlp:jar:1.7.0:compile

But we need this dependency at runtime, otherwise we get an error.

Caused by: org.apache.druid.opentelemetry.shaded.io.opentelemetry.sdk.autoconfigure.spi.ConfigurationException: OTLP gRPC Trace Exporter enabled but opentelemetry-exporter-otlp not found on classpath. Make sure to add it as a dependency to enable this feature.

[xvrl]

instead of ignoring it, it might be enough to make opentelemetry-exporter-otlp a runtime scope dependency to make it clear it's not used at compile time but required at runtime.

[IvanVan]

yeah, sounds good
I tried to push a commit to this PR, but I don't have permissions
Permission to confluentinc/druid.git denied to IvanVan.

Also I don't know how to update PR upstream, because there is the same issue there and I want to add info about tracestate
I can create another PR to upstream from my own fork
What do you think of it? @xvrl

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