test : added unit tests for goals-sync-utils.ts

[tmdeveloper007]

Closes #2862.

Summary of What Has Been Done:
Added a comprehensive test suite for the goals-sync-utils.ts utility module covering extractValidRepoFromGoal function.

Changes Made:

• Created test/goals-sync-utils.test.ts with 15 test cases
• Tested extractValidRepoFromGoal with valid repo from all three possible fields (repo, repository, repo_name)
• Tested field precedence (repo takes priority over repository and repo_name)
• Tested null/undefined/empty/whitespace values in all fields
• Tested invalid GitHub repo identifier formats
• Tested whitespace trimming

Impact it Made:
Increases test coverage and ensures repository extraction from goal rows handles all field variations and rejects invalid formats.

[github-actions]

GSSoC Label Checklist 🏷️

@Priyanshu-byte-coder — please apply the appropriate labels before merging:

Difficulty (pick one):

• level:beginner — 20 pts
• level:intermediate — 35 pts
• level:advanced — 55 pts
• level:critical — 80 pts

Quality (optional):

• quality:clean — ×1.2 multiplier
• quality:exceptional — ×1.5 multiplier

Validation (required to score):

• gssoc:approved — counts for points
• gssoc:invalid / gssoc:spam / gssoc:ai-slop — does not score

Type labels (type:*) are auto-detected from files and title. Review and adjust if needed.
Points formula: (difficulty × quality_multiplier) + type_bonus