[BUG] Add Snapshot Maximum Count to the Settings

[yardenshoham]

Describe the bug

This setting is missing

Additional context

#7896
#7894

[longhorn-io-github-bot]

Pre Ready-For-Testing Checklist

• Where is the reproduce steps/test steps documented?
  The reproduce steps/test steps are at: Install LH via helm chart without error.

• Is there a workaround for the issue? If so, where is it documented?

• Does the PR include the explanation for the fix or the feature? yes

• Does the PR include deployment change (YAML/Chart)? If so, where are the PRs for both YAML file and Chart?
  The PR for the YAML change is at: chart: Add Snapshot Maximum Count to the Settings #7896
  The PR for the chart change is at: chart: Add Snapshot Maximum Count to the Settings #7896

• Have the backend code been merged (Manager, Engine, Instance Manager, BackupStore etc) (including backport-needed/*)?
  The PR is at chart: Add Snapshot Maximum Count to the Settings #7896

[innobead]

@FrankYang0529 Please help drive this to ready for testing. Thanks.

[roger-ryao]

Verified on master-head 20240312

• longhorn master-head 88c49e7

The test steps

#7906 (comment)

Result Passed

• Install LH via helm chart without error.
• require/chart : Installed Longhorn using Helm chart and modified snapshotMaxCount to 10, and it took effect.