simplify bucket metadata lookups for versioning/object locking

[harshavardhana]

Description

simplify bucket metadata lookups for versioning/object locking

Motivation and Context

optimize bucket metadata usage and readability improvements

How to test this PR?

Nothing special to test, just optimal usage of bucket metadata.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Optimization (provides speedup with no functional changes)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• Fixes a regression (If yes, please add commit-id or PR # here)
• Unit tests added/updated
• Internal documentation updated
• Create a documentation update request here