KAFKA-18803: The acls would appear at the wrong level of the metadata shell "tree"

[Yunyung]

see #18845 (comment)

Committer Checklist (excluded from commit message)

• Verify design and implementation
• Verify test coverage and CI build status
• Verify documentation (including upgrade notes)

[mumrah]

@Yunyung the fix LGTM. Can you do two things:

1. Manually test this patch by creating some ACLs and showing the output from metadata shell
2. Add a unit test for the MetadataImageNode to ensure we see the "acls" node correctly

[Yunyung]

1. Manually test this patch by creating some ACLs and showing the output from metadata shell

Before:

$ ./bin/kafka-metadata-shell.sh --snapshot /tmp/kraft-combined-logs/__cluster_metadata-0/00000000000000000000.log
Loading...
[2025-02-16 13:58:14,107] ERROR Ignoring control record with type KRAFT_VERSION at offset 1 (org.apache.kafka.metadata.util.SnapshotFileReader)
[2025-02-16 13:58:14,110] ERROR Ignoring control record with type KRAFT_VOTERS at offset 2 (org.apache.kafka.metadata.util.SnapshotFileReader)
Starting...
[ Kafka Metadata Shell ]
>> ls image/acls/
5Mu_djJ5QZaw79Fc3URLfw
>>

After:

$ ./bin/kafka-metadata-shell.sh --snapshot /tmp/kraft-combined-logs/__cluster_metadata-0/00000000000000000000.log
Loading...
[2025-02-16 21:59:06,250] ERROR Ignoring control record with type KRAFT_VERSION at offset 1 (org.apache.kafka.metadata.util.SnapshotFileReader)
[2025-02-16 21:59:06,251] ERROR Ignoring control record with type KRAFT_VOTERS at offset 2 (org.apache.kafka.metadata.util.SnapshotFileReader)
Starting...
[ Kafka Metadata Shell ]
>> ls image/acls/
byId
>> ls image/acls/byId/
cnTIY8C5R5-PIm0EKywItg
>> 

2. Add a unit test for the MetadataImageNode to ensure we see the "acls" node correctly

Done.

Thanks for the review, PTAL.

[chia7712]

cherry-pick to 4.0, 3.9 and 3.8