fix(inputs.snmp_trap): Handle octet strings

[JuhaKS]

Summary

As discussed in #9113, any octetString data that goes beyond valid UTF-8 values will first be converted to a Golang string as the data is instantiated as a Metric. This step changes the presentation of the data but doesn't yet destroy anything, but the following json.Marshal that happens in use cases where the desired output format is JSON, the non-UTF characters get replaced with Unicode replacement characters, overwriting data octets in the process

This fix adds a check for SNMP data of type OctetString, that validates whether the data can be converted into valid UTF-8 or not. If yes, the data is passed unchanged. If not, the data is considered hex and processed with hex.EncodeToString. The end result with our test material is that the hex format timestamp is then passed correctly through processing, preserving both the data and its original presentation unchanged

Checklist

• No AI generated code was used in this PR

Related issues

resolves #9113

[telegraf-tiger]

Thanks so much for the pull request!
🤝 ✒️ Just a reminder that the CLA has not yet been signed, and we'll need it before merging. Please sign the CLA when you get a chance, then post a comment here saying !signed-cla

[JuhaKS]

!signed-cla as CCLA

[telegraf-tiger]

Download PR build artifacts for linux_amd64.tar.gz, darwin_arm64.tar.gz, and windows_amd64.zip.
Downloads for additional architectures and packages are available below.

☺️ This pull request doesn't significantly change the Telegraf binary size (less than 1%)

📦 Click here to get additional PR build artifacts

Artifact URLs

DEB	RPM	TAR GZ	ZIP
amd64.deb	aarch64.rpm	darwin_amd64.tar.gz	windows_amd64.zip
arm64.deb	armel.rpm	darwin_arm64.tar.gz	windows_arm64.zip
armel.deb	armv6hl.rpm	freebsd_amd64.tar.gz	windows_i386.zip
armhf.deb	i386.rpm	freebsd_armv7.tar.gz
i386.deb	ppc64le.rpm	freebsd_i386.tar.gz
mips.deb	riscv64.rpm	linux_amd64.tar.gz
mipsel.deb	s390x.rpm	linux_arm64.tar.gz
ppc64el.deb	x86_64.rpm	linux_armel.tar.gz
riscv64.deb		linux_armhf.tar.gz
s390x.deb		linux_i386.tar.gz
		linux_mips.tar.gz
		linux_mipsel.tar.gz
		linux_ppc64le.tar.gz
		linux_riscv64.tar.gz
		linux_s390x.tar.gz

[powersj]

@JuhaKS,

!signed-cla as CCLA

When did you send in the signed CCLA? Trying to ensure you get added to the right list.

[JuhaKS]

@JuhaKS,

!signed-cla as CCLA

When did you send in the signed CCLA? Trying to ensure you get added to the right list.

It was sent to community@influxdata.com on 24.01.2024 11:53 EET

[powersj]

It was sent to community@influxdata.com on 24.01.2024 11:53 EET

Thanks! I'll follow up with folks internally.

[powersj]

!signed-cla

[powersj]

Thanks!

[srebhan]

Thank you very much for your contribution @JuhaKS!