fix: show missing retention policies

[jansimonb]

Fix parsing result of SHOW RETENTION POLICIES. Enterprise v1.12.1 newly returns 2 new columns in the result:

• futureWriteLimit
• pastWriteLimit

These 2 new columns were unknown to chronograf yet, so the result parsing had to be fixed.

Now the code supports 2 result formats:

• 5-column format: [name, duration, shardGroupDuration, replicaN, default]
• 7-column format: [name, duration, shardGroupDuration, replicaN, futureWriteLimit, pastWriteLimit, default]

Additionally, error logging was added to make it easier to detect similar issues in the future.

• CHANGELOG.md updated with a link to the PR (not the Issue)
• Well-formatted commit messages
• Rebased/mergeable
• Tests pass
• Any changes to etc/Dockerfile_build have been pushed to DockerHub, and the changes have been added to .circleci/config.yml
• swagger.json updated (if modified Go structs or API)
• Sign CLA (if not already signed)

[bednar]

The implementation looks good. Please add a few tests similar to:

chronograf/influx/permissions_test.go

Line 347 in c8fff05

func Test_showResults_Permissions(t *testing.T) {

[bednar]

LGTM 🚀

[karel-rehor]

1.Rebuilt Chronograf in circle-ci Chronograf 202508121131~92117c5 (git: 92117c55a2571368da12f66924ab14d37d20f38e) then downloaded and ran it on local Ubuntu 22.0.4.

2.Started a local dockerized influxdb:1.8 and connected it to the running chronograf.

3. Tested it via CLI with $ influx v1 shell --host http://localhost:18086 and then successfully looked up retention policies. e.g.

> SHOW RETENTION POLICIES ON mydb
> SHOW RETENTION POLICIES ON _internal

4. Then checked the same results in chronograf > influxdb admin. Retention policies render successfully.

Conclusion, looks corrrect.

[karel-rehor]

Short manual test result is in comment in conversation. Looks correct to me. 🚴 🏁