fix: add registry does not honor default main/master branch

[ritesh-harihar]

Description
This occurred because when users do not explicitly pass a --ref string, Nomad Pack assumed the target was "latest". For performance reasons, a previous PR introduced logic that appended ?depth=1 to the Go-Getter URL for "latest" downloads to enforce a shallow clone.

However, forcing depth=1 without specifying a branch name causes the underlying git clone mechanism inside go-getter to eagerly assume the master branch on certain repository schemas. For registries defaulting to main, this throws an error.

Fix:
This PR repairs the broken behavior by removing the hardcoded ?depth=1 parameter injection for latest registries entirely:

• Refactored the cloneRemoteGitRegistry URL-building logic out into a clean helper function (buildGoGetterGitURL).
• Removed the else condition that appended ?depth=1 when IsLatest() evaluated to true. Without the depth restriction, Go- Getter and Git are allowed to naturally negotiate the remote's actual default symbolic $HEAD (resolving successfully to main without throwing the "master not found" exception).

JIRA Ticket

Reminders

• Add CHANGELOG.md entry

• If a change needs to be reverted, we will roll out an update to the code within 7 days.

Changes to Security Controls

Are there any changes to security controls (access controls, encryption, logging) in this pull request? If so, explain.