[BUG] non-feature columns get converted into string columns when get result dataframe

[loomlike]

Willingness to contribute

No. I cannot contribute a bug fix at this time.

Feathr version

0.9.0

System information

• OS Platform and Distribution (e.g., Linux Ubuntu 20.0): Linux Ubuntu 20.0)
• Python version: 3.8
• Spark version, if reporting runtime issue: 3.3.1

Describe the problem

non-feature columns of the original source data get converted into string column, e.g. 0 (int) -> "0", True (bool) -> "True" string values when getting the feature result.

Tracking information

No response

Code to reproduce bug

No response

What component(s) does this bug affect?

• [ ] Python Client: This is the client users use to interact with most of our API. Mostly written in Python.
• [X] Computation Engine: The computation engine that execute the actual feature join and generation work. Mostly in Scala and Spark.
• [ ] Feature Registry API: The frontend API layer supports SQL, Purview(Atlas) as storage. The API layer is in Python(FAST API)
• [ ] Feature Registry Web UI: The Web UI for feature registry. Written in React