[TASK] Ensure the Go version in Dockerfile.dapper matches go.mod for all Longhorn components

[ejweber]

What's the task? Please describe

The go.mod files for most (if not all) Longhorn components references Go 1.21 on the master, v1.5.x, and v1.4.x branches. However, in many cases, the Dockerfile.dapper (which actually determines the version of the Go compiler we will use) references an older version of Go.

Describe the sub-tasks

• Update longhorn-manager master.
• Update longhorn-manager v1.5.x.
• Update longhorn-manager v1.4.x.
• Update longhorn-instance-manager master.
• Update longhorn-instance-manager v1.5.x.
• Update longhorn-instance-manager v1.4.x.
• Update backing-image-manager master.
• Update backing-image-manager v1.5.x.
• Update backing-image-manager v1.4.x.
• Update share-manager master.
• Update share-manager v1.5.x.
• Update share-manager v1.4.x.

I checked the following components, which require no change:

• longhorn-engine master
• longhorn-engine v1.5.x
• longhorn-engine v1.4.x

[ejweber]

I created containers for all components with bumped versions and am running end-to-end tests on all three branches. If the tests pass, we should be safe to merge all the PRs.

[ejweber]

master results links:

• https://ci.longhorn.io/job/private/job/longhorn-tests-regression/5392/testReport/
• https://ci.longhorn.io/job/private/job/longhorn-tests-regression/5385/testReport/

master results failures:

• tests.test_node.test_node_default_disk_labeled failed both times, but it also regularly fails without the patch.
• tests.test_metric.test_volume_metrics[default] failed once.
• tests.test_ha.test_auto_remount_with_subpath failed once.

[ejweber]

v1.5.x results links:

• https://ci.longhorn.io/job/private/job/longhorn-tests-regression/5386/testReport/
• https://ci.longhorn.io/job/private/job/longhorn-tests-regression/5393/testReport/

v1.5.x results failures:

• tests.test_csi.test_csi_minimal_volume_size failed both times, but it also regularly fails without the patch.
• tests.test_settings.test_setting_concurrent_volume_backup_restore_limit_should_not_effect_dr_volumes[s3] failed once.
• tests.test_basic.test_filesystem_trim[ext4] failed once.
• tests.test_metric.test_volume_metrics[default] failed once.

[ejweber]

v1.4.x results link:

• https://ci.longhorn.io/job/private/job/longhorn-tests-regression/5387/testReport/

v1.4.x results failures:

• All 16 test_csi_snapshotter tests failed, but this also happened when I ran a regression unpatched. I do not think these failures are related to the changes.
• tests.test_kubernetes.test_kubernetes_status, tests.test_kubernetes.test_backup_kubernetes_status[s3], and tests.test_kubernetes.test_backup_kubernetes_status[nfs] are also regularly failing without the patch (https://ci.longhorn.io/job/public/job/v1.4.x/job/v1.4.x-longhorn-tests-sles-amd64/407/testReport/).

[longhorn-io-github-bot]

Pre Ready-For-Testing Checklist

• Where is the reproduce steps/test steps documented?
  These changes should have no noticeable impact. If regression testing remains stable, we can close this issue.

• Have the backend code been merged (Manager, Engine, Instance Manager, BackupStore etc) (including backport-needed/*)?
  See all the above linked PRs.

• Which areas/issues this PR might have potential impacts on?
  Behavioral changes resulting from the Go version change may be subtle and hard to trace back to these PRs.

[innobead]

All merged.