[prism] Fail pipeline execution properly on descriptor build errors.

[lostluck]

Add the missing check to trigger pipeline failures at stage construction.

Related to #28126 and #28187

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[codecov]

Codecov Report

Merging #28170 (25aaa95) into master (fdf3dfc) will decrease coverage by 0.02%.
Report is 1 commits behind head on master.
The diff coverage is 44.92%.

@@            Coverage Diff             @@
##           master   #28170      +/-   ##
==========================================
- Coverage   72.30%   72.29%   -0.02%     
==========================================
  Files         678      678              
  Lines       99799    99838      +39     
==========================================
+ Hits        72163    72175      +12     
- Misses      26074    26084      +10     
- Partials     1562     1579      +17     

Flag	Coverage Δ
go	53.65% <44.92%> (-0.03%)	⬇️

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

Files Changed	Coverage Δ
...am/runners/prism/internal/engine/elementmanager.go	80.91% <0.00%> (-1.14%)	⬇️
sdks/go/pkg/beam/runners/prism/internal/execute.go	88.11% <22.22%> (-2.65%)	⬇️
sdks/go/pkg/beam/runners/prism/internal/stage.go	83.24% <30.76%> (-2.17%)	⬇️
...go/pkg/beam/runners/prism/internal/handlerunner.go	84.00% <33.33%> (-2.31%)	⬇️
sdks/go/pkg/beam/runners/prism/internal/coders.go	87.97% <63.15%> (-4.08%)	⬇️
...o/pkg/beam/runners/prism/internal/worker/worker.go	48.37% <100.00%> (+1.24%)	⬆️

... and 2 files with indirect coverage changes

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[byronellis]

LGTM