test(frontend): cover isSink and isPythonUdf helpers

[Ma77Ball]

What changes were proposed in this PR?

• Add unit tests for the isSink helper covering substring matching, case-insensitivity, and non-matches.
• Add unit tests for the isPythonUdf helper covering each of the three Python UDF operator types and non-matches.

Any related issues, documentation, discussions?

Closes: #6674

How was this PR tested?

• Run: cd frontend && node --max-old-space-size=8192 ./node_modules/nx/dist/bin/nx.js test gui --watch=false --include=src/app/workspace/service/workflow-graph/model/workflow-graph.spec.ts, expect the suite passing.
• Test-only change; no production code is modified.

Was this PR authored or co-authored using generative AI tooling?

Co-authored with Claude Opus 4.8 in compliance with ASF

[github-actions]

Automated Reviewer Suggestions

Based on the git blame history of the changed files, we recommend the following reviewers:

• Contributors with relevant context: @aglinxinyuan
  You can notify them by mentioning @aglinxinyuan in a comment.

[Copilot]

Pull request overview

This PR adds frontend unit test coverage for two helper functions (isSink and isPythonUdf) in the workflow graph model, improving confidence in operator-type classification behavior used by the workflow editor.

Changes:

• Added unit tests for isSink covering substring matching, case-insensitivity, and non-matching operator types.
• Added unit tests for isPythonUdf covering all supported Python UDF v2 operator types plus negative cases.
• Updated imports in workflow-graph.spec.ts to reference the helper functions and related operator-type constants.

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[aglinxinyuan]

Merged main to trigger coverage report.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.65%. Comparing base (429be11) to head (cd47f5c).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6675      +/-   ##
============================================
- Coverage     77.31%   76.65%   -0.66%     
+ Complexity     3524     3452      -72     
============================================
  Files          1161     1161              
  Lines         45920    45916       -4     
  Branches       5099     5098       -1     
============================================
- Hits          35501    35198     -303     
- Misses         8839     9183     +344     
+ Partials       1580     1535      -45     

Flag	Coverage Δ		*Carryforward flag
access-control-service	70.00% <ø> (ø)		Carriedforward from e2e4418
agent-service	76.76% <ø> (ø)		Carriedforward from e2e4418
amber	67.33% <ø> (-1.77%)	⬇️	Carriedforward from e2e4418
computing-unit-managing-service	20.49% <ø> (ø)		Carriedforward from e2e4418
config-service	66.66% <ø> (ø)		Carriedforward from e2e4418
file-service	67.21% <ø> (ø)		Carriedforward from e2e4418
frontend	82.57% <100.00%> (-0.01%)	⬇️
notebook-migration-service	78.94% <ø> (ø)		Carriedforward from e2e4418
pyamber	92.15% <ø> (ø)		Carriedforward from e2e4418
workflow-compiling-service	55.14% <ø> (ø)		Carriedforward from e2e4418

*This pull request uses carry forward flags. Click here to find out more.

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[aglinxinyuan]

Closing as it doesn't increase coverage: #6675 (comment)

[aglinxinyuan]

Will reevaluate after fixing the Codecov Report.