Fix log level of when starting a raft node

[miagilepner]

Description

A non-removed raft node would always print this error log line, which could be confusing for users. Switch the log line to debug level.

TODO only if you're a HashiCorp employee

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  break any tests. Sometimes ENT only tests rely on public functions in CE
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[kubawi]

LGTM

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CI Results:
All Go tests succeeded! ✅

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Build Results:
All builds succeeded! ✅