closedts: log err when incoming stream drops

[aliher1911]

Currently we don't log error in the warning if incoming closedts stream is dropped by remote. Since those events are not frequent it would be beneficial to log actual error as we don't expect anything other than EOF which is handled separately.
This PR adds error to the log message.

Epic: none

Release note: None

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[cockroach-teamcity]

This change is 

[aliher1911]

TFTR

bors r+

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)

[sean-]

@aliher1911 or @erikgrinaker , any objection if I blathers backport 23.1 22.2 this PR?

[blathers-crl]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

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error getting backport branch release-22.2`: unexpected status code: 404 Not Found

Backport to branch 22.2` failed. See errors above.

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error getting backport branch release-this: unexpected status code: 404 Not Found

Backport to branch this failed. See errors above.

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error getting backport branch release-PR?: unexpected status code: 404 Not Found

Backport to branch PR? failed. See errors above.

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_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}