[SourceKit] Suppress oslog_invalid_log_message diagnostic in live issues
The index build skips *all* function bodies, including inlinable. The
`OSLogOptimization` pass expects SIL for inlinable bodies and thus
outputs a spurious diagnostic for live issues when the
`OSLogInterpolation` extension is in a separate module to the log
statement.
Ignore this for now, but we may need to re-evaluate if this becomes a
more widespread problem.
Resolves rdar://79100763