release-24.1: changefeedccl: enable verbose logs for a few schema change unit tests

[andyyang890]

Backport 3/3 commits from #131780.

/cc @cockroachdb/release

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changefeedccl/kvfeed: add debug logs around schema change boundary types

Release note: None

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changefeedccl: add debug logs around when processors move to draining

Release note: None

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changefeedccl: enable verbose logs for a few schema change unit tests

We're seeing that some changefeed unit tests involving schema changes
are sometimes flaking when using a core changefeed. This patch enables
verbose logs that will provide more information about what the kv feed
is doing when it sees the schema change and when processors are moving
to draining.

Release note: None

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Informs #131186
Informs #130404
Informs #129777
Informs #129226
Informs #129045

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Release justification: low-risk addition of logs

[blathers-crl]

Thanks for opening a backport.

Please check the backport criteria before merging:

• Backports should only be created for serious
  issues or test-only changes.
• Backports should not break backwards-compatibility.
• Backports should change as little code as possible.
• Backports should not change on-disk formats or node communication protocols.
• Backports should not add new functionality (except as defined
  here).
• Backports must not add, edit, or otherwise modify cluster versions; or add version gates.
• All backports must be reviewed by the owning areas TL. For more information as to how that review should be conducted, please consult the backport
  policy.

If your backport adds new functionality, please ensure that the following additional criteria are satisfied:

• There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
• The new functionality is additive-only and only runs for clusters which have specifically “opted in” to it (e.g. by a cluster setting).
• New code is protected by a conditional check that is trivial to verify and ensures that it only runs for opt-in clusters. State changes must be further protected such that nodes running old binaries will not be negatively impacted by the new state (with a mixed version test added).
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• Your backport must be accompanied by a post to the appropriate Slack
  channel (#db-backports-point-releases or #db-backports-XX-X-release) for awareness and discussion.

Also, please add a brief release justification to the body of your PR to justify this
backport.

[cockroach-teamcity]

This change is