Ignore Access Log in metrics collection if Formats differ

[aphralG]

Proposed changes

When more than one log format is specified for a access log in the nginx config, otel panics trying to monitor the same log with two different formats.

If its the same access log read from the config but the format is different the following will be logged as a Warning:
time=2025-05-29T10:01:49.448Z level=WARN msg="Found duplicate access log with different formats. Multiple log formats are not supported in the same access log, will not be collected" access_log=/var/log/nginx/access.log

If its the same access log read from the config but with the same format the following will be logged in Debug:
time=2025-05-29T10:04:07.231Z level=DEBUG msg="Found duplicate access log, skipping" access_log=/var/log/nginx/access.log

Checklist

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• If applicable, I have checked that any relevant tests pass after adding my changes
• If applicable, I have updated any relevant documentation (README.md)
• If applicable, I have tested my cross-platform changes on Ubuntu 22, Redhat 8, SUSE 15 and FreeBSD 13