fix: fix string size calculation BED-7260

[bsheth711]

Description

Describe your changes in detail

This PR fixes calculation of string size in memory. Currently the string header size is multiplied by the length of the string, leading to a significant overestimation in size. Instead, the string header size should be added to the length of the string as len(str) already returns the number of bytes in the string. See: https://pkg.go.dev/builtin#len

Motivation and Context

Why is this change required? What problem does it solve?

This fix resolves a bug discovered investigating BED-7260. Specifically, it was discovered that memory consumption was being overreported by DAWGs due to incorrectly calculating string size in memory, causing traversals to be cancelled.

How Has This Been Tested?

This has been tested locally with unit tests and observationally running graph queries.

Screenshots (optional):

Types of changes

• Bug fix (non-breaking change which fixes an issue)

[coderabbitai]

Walkthrough

These changes correct the memory size calculation for strings in the size utility package by switching from multiplication to addition, and update corresponding test expectations to reflect the revised calculations.

Changes

Cohort / File(s)	Summary
Size calculation logic util/size/size.go	Changed string size calculation from multiplication to addition (totalSize *= Size(len(typedValue)) → totalSize += Size(len(typedValue))), affecting how string inner allocations are accounted for in total size.
Direct size utility tests util/size/size_test.go	Updated expected values in TestOfAny for string and slice types with detailed breakdown comments explaining header sizes and totals (0x40→0x14, 0x108→0x57, 0x44→0x36).
Graph properties tests graph/properties_test.go	Adjusted SizeOf() test assertions to reflect updated calculations (440→146, 296→105, 256→78, 1600→478).

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Suggested reviewers

• zinic
• ALCooper12

Poem

🐰 A calculation fixed with care,
From times to plus, a change so fair,
String sizes now reported true,
Tests updated, all made new,
Size allocation's mystery solved! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change in the pull request, which is fixing a bug in string size calculation as documented in the PR objectives.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch BED-7260-fix-string-size-calculation

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[zinic]