feat(helm): make kubearmor-snitch image configurable via Helm values

[UtkarshUmre]

Purpose of PR?:
The kubearmor-snitch container image is hardcoded to kubearmor/kubearmor-snitch:latest, creating issues in enterprise environments with admission controllers that restrict image pulls to trusted private registries. This PR makes the kubearmor-snitch image configurable via Helm values, similar to how other KubeArmor components work, allowing users to specify custom repositories, tags, and image pull policies.

Fixes #1975

Does this PR introduce a breaking change?
No

If the changes in this PR are manually verified, list down the scenarios covered::

• Default Behavior (Backward Compatibility)
• Custom Image Configuration
• imagePinning=true Mode Compatibility
• Helm Chart Validation

Additional information for reviewer? :
Mention if this PR is part of any design or a continuation of previous PRs

Checklist:

• Bug fix. Fixes #
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• PR Title follows the convention of <type>(<scope>): <subject>
• Commit has unit tests
• Commit has integration tests