fix(ci): fix coverage report merge and flags

[yangxk1]

Reason for this PR

close #752

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.77%. Comparing base (1bb0468) to head (e93f5ac).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #759      +/-   ##
============================================
- Coverage     77.77%   75.77%   -2.00%     
- Complexity      234      470     +236     
============================================
  Files            25       82      +57     
  Lines           918     8550    +7632     
  Branches         49      964     +915     
============================================
+ Hits            714     6479    +5765     
- Misses          167     1873    +1706     
- Partials         37      198     +161     

Flag	Coverage Δ
cpp	70.85% <ø> (?)
java-info	77.77% <ø> (?)
pyspark	95.11% <ø> (?)
spark	81.32% <ø> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

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[Copilot]

Pull Request Overview

This PR fixes Codecov coverage reporting configuration by updating flag names and enabling carryforward functionality. The changes ensure proper coverage report merging across different components of the GraphAr project.

• Fixed incorrect singular flag parameter to plural flags in GitHub Actions workflows
• Added carryforward: true to all coverage flags in codecov.yml to preserve coverage data when jobs don't run

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
codecov.yml	Added carryforward configuration for all coverage flags
.github/workflows/spark.yaml	Fixed flag parameter name from singular to plural
.github/workflows/pyspark.yml	Fixed flag parameter name from singular to plural
.github/workflows/java-info.yml	Fixed flag parameter name from singular to plural
.github/workflows/ci.yml	Fixed flag parameter name from singular to plural

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