Perform forecaster strategy parameter validation on init

[baggiponte]

Was chatting with @FBruzzesi about functime and realised this does not raise.

from functime.forecasting import linear_model

model = linear_model(freq="1mo", lags=4, strategy="ashdfaskldj")

model.name

Validation happens in .fit(). I guess we should move this validation on forecaster definition.

[srihitha2005]

Hi ,
I'm interested in contributing to this repository. I came across this issue and was wondering if I could help resolve it.
Before I start working on it, I wanted to check if the issue is still open and if anyone else is currently working on it. Could you please let me know the status of this issue?