feat: make get_online_feature to infer feature schema from the output if transformation specified

## Expected Behavior
get_online_feature should respect the transformation flow.
## Current Behavior
Copy from the slack:
Hello All, I was exploring Batch Feature View. I linked it to a batch source , a method as udf, a udf string and a transformation object as feature_transformation. Now I can see the features present in the batch source on feast ui but no information on udf or transformation, or the transformed features created using transformation. Also want to understand how to use batch feature view correctly to have those transformations applied to the batch source.

## Steps to reproduce

### Specifications

- Version:
- Platform:
- Subsystem:

## Possible Solution