fix(common.socket): Use read buffer size config setting as a datagram reader buffer size.

[MarekZydor]

Summary

Currently, the datagram read buffer size is fixed at 64 KB, which is leading
to data loss when receiving large datagrams (metrics) over Unix Domain Sockets (unixgram).
This fix ensures that the buffer size matches read-buffer-size
configuration, preventing truncation of incoming data.

Checklist

• No AI generated code was used in this PR

Related issues

resolves #16118

[srebhan]

@MarekZydor thanks for your contribution! Please fix the unit-test so we can get this merged.

[srebhan]

Thanks @MarekZydor for the update. Two small comments then we are good to go I think...

[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 increases the Telegraf binary size by 2.31 % for linux amd64 (new size: 262.4 MB, nightly size 256.5 MB)

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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

[srebhan]

Thanks @MarekZydor!