Feat: add mode in steps for step group

[FogDong]

Description of your changes

Fixes #

I have:

• Read and followed KubeVela's contribution process.
• Related Docs updated properly. In a new feature or configuration option, an update to the documentation is necessary.
• Run yarn lint to ensure the frontend changes are ready for review.
• Run make reviewableto ensure the server changes are ready for review.
• Added backport release-x.y labels to auto-backport this PR if necessary.

Special notes for your reviewer

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.08 🎉

Comparison is base (49a3a03) 61.03% compared to head (92076fc) 61.11%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #746      +/-   ##
==========================================
+ Coverage   61.03%   61.11%   +0.08%     
==========================================
  Files         106      106              
  Lines       18589    18591       +2     
==========================================
+ Hits        11345    11362      +17     
+ Misses       5849     5836      -13     
+ Partials     1395     1393       -2     

Flag	Coverage Δ
apiserver-unittests	33.17% <50.00%> (-0.01%)	⬇️
server-e2e-tests	49.83% <100.00%> (+0.02%)	⬆️

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

Impacted Files	Coverage Δ
pkg/server/domain/model/workflow.go	100.00% <ø> (ø)
pkg/server/domain/service/application.go	61.80% <100.00%> (-0.17%)	⬇️
pkg/server/domain/service/pipeline.go	70.35% <100.00%> (+0.02%)	⬆️

... and 6 files with indirect coverage changes

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[barnettZQG]

LGTM