support 1-to-n mapping function for transformOverride

[farzad-sedghi]

fixing https://github.com/spotify/scio/issues/4400

[codecov[bot]]

Codecov Report

Merging #4484 (a38517c) into main (36935c1) will decrease coverage by 0.22%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #4484      +/-   ##
==========================================
- Coverage   60.48%   60.26%   -0.23%     
==========================================
  Files         275      275              
  Lines        9882    10046     +164     
  Branches      438      842     +404     
==========================================
+ Hits         5977     6054      +77     
- Misses       3905     3992      +87     

Impacted Files	Coverage Δ
...a/com/spotify/scio/testing/TransformOverride.scala	100.00% <100.00%> (ø)
...om/spotify/scio/elasticsearch/CoderInstances.scala	44.11% <0.00%> (-5.89%)	:arrow_down:
...om/spotify/scio/elasticsearch/CoderInstances.scala	42.42% <0.00%> (-5.86%)	:arrow_down:
...com/spotify/scio/bigquery/types/TypeProvider.scala	47.22% <0.00%> (-2.78%)	:arrow_down:
...la/com/spotify/scio/bigquery/client/BigQuery.scala	22.44% <0.00%> (-2.56%)	:arrow_down:
...rc/main/scala/com/spotify/scio/util/ScioUtil.scala	59.25% <0.00%> (-2.28%)	:arrow_down:
...n/scala/com/spotify/scio/extra/annoy/package.scala	80.00% <0.00%> (-2.06%)	:arrow_down:
...la/com/spotify/scio/tensorflow/TFRecordCodec.scala	96.00% <0.00%> (-1.92%)	:arrow_down:
...cala/com/spotify/scio/coders/KryoAtomicCoder.scala	70.07% <0.00%> (-1.70%)	:arrow_down:
...e/src/main/scala/com/spotify/scio/ScioResult.scala	84.31% <0.00%> (-1.41%)	:arrow_down:
... and 39 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.