Fix save load roundtrip

[ahuang11]

Upon loading DbtCliProfile, the original fields from the specialized TargetConfigs gets dropped. The following used to have a credentials field.

DbtCliProfile(name='bigbird', target='abc', target_configs=TargetConfigs(extras=None, type='bigquery', threads=20), global_configs=None)
Expected

Closes #114

Example

Screenshots

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