[processor/sumologic] Export config types to enable Go API usage

[dmitryax]

The sumologicprocessor's Config struct contains several unexported field types that prevent users from programmatically creating configurations via Go API:

See discussion #45757 (comment)

[github-actions]

Pinging code owners:

• processor/sumologic: @rnishtala-sumo @chan-tim-sumo @amdprophet

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