Optimize WeakAttribute.changedValue

[Kyle-Ye]

Summary

This PR optimizes the WeakAttribute.changedValue implementation and updates the bump_ag_pr.sh script for better DarwinPrivateFrameworks integration.

Changes

• Optimized WeakAttribute.changedValue implementation
• Updated bump_ag_pr.sh script for improved PR workflow

Related PRs

• Related to Update AttributeGraph from OpenAttributeGraph bugfix/weak_attr DarwinPrivateFrameworks#24
• This PR generated the corresponding updates in DarwinPrivateFrameworks

Test plan

• Build successfully
• Tests pass
• Generated DarwinPrivateFrameworks PR Complete OGAttribute API #24 successfully merged

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 5.49%. Comparing base (80d85eb) to head (b8f91c0).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...nAttributeGraph/Attribute/Weak/WeakAttribute.swift	0.00%	1 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## main #185 +/- ##
========================================
+ Coverage 4.81% 5.49% +0.68% 
========================================
Files 28 25 -3 Lines 831 655 -176 ========================================
- Hits 40 36 -4 + Misses 791 619 -172 

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