Add default search space for standard trainers

[LittleLittleCloud]

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#6577

the offline process of fewshot/zeroshot AutoML needs to be run on a fixed search space. This PR builds fixed search spaces for standard trainers using Microsoft.ML.SearchSpace

[michaelgsharp]

@LittleLittleCloud "Found conflicts between different versions of "System.Text.Json" that could not be resolved." Make sure we are using the same versions everywhere.

[LittleLittleCloud]

/azp run

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Azure Pipelines successfully started running 2 pipeline(s).

[LittleLittleCloud]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[LittleLittleCloud]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[codecov]

Codecov Report

Merging #6576 (cb3083b) into main (d239fda) will increase coverage by 0.02%.
The diff coverage is 72.97%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6576      +/-   ##
==========================================
+ Coverage   68.39%   68.41%   +0.02%     
==========================================
  Files        1174     1176       +2     
  Lines      248047   248210     +163     
  Branches    25909    25915       +6     
==========================================
+ Hits       169647   169812     +165     
- Misses      71626    71647      +21     
+ Partials     6774     6751      -23     

Flag	Coverage Δ
Debug	68.41% <72.97%> (+0.02%)	⬆️
production	62.80% <53.39%> (+0.02%)	⬆️
test	88.87% <97.56%> (-0.02%)	⬇️

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

Impacted Files	Coverage Δ
...t.ML.SearchSpace/Converter/SearchSpaceConverter.cs	0.00% <0.00%> (ø)
...rc/Microsoft.ML.SearchSpace/Option/ChoiceOption.cs	97.56% <ø> (ø)
src/Microsoft.ML.SearchSpace/Option/NestOption.cs	30.13% <ø> (-26.03%)	⬇️
src/Microsoft.ML.SearchSpace/Option/OptionBase.cs	100.00% <ø> (ø)
...soft.ML.SearchSpace/Option/UniformNumericOption.cs	97.46% <ø> (ø)
...icrosoft.ML.StandardTrainers/LdSvm/LdSvmTrainer.cs	96.62% <ø> (ø)
.../Standard/LogisticRegression/LbfgsPredictorBase.cs	61.34% <ø> (ø)
...StandardTrainers/Standard/Online/AveragedLinear.cs	60.33% <ø> (ø)
...t.ML.StandardTrainers/Standard/Online/LinearSvm.cs	80.31% <ø> (ø)
...L.StandardTrainers/Standard/Online/OnlineLinear.cs	79.43% <ø> (ø)
... and 21 more