text: Title: Set `time2idx=False` in  expression_provider kwargs will cause `unsupported operand type(s) for +: 'Timedelta' and 'int'`
  Body: ## 🐛 Bug Description
  
  <!-- A clear and concise description of what the bug is. -->
  
  ## To Reproduce
  
  Steps to reproduce the behavior:
  
  1. `qlib.init(expression_provider={"class": "LocalExpressionProvider", "kwargs": dict(time2idx=False)})`
  1. get feature with P operator "P($$roewa_q)"
  
  ## Expected Behavior
  
   no error
  
  ## Screenshot
  ![image](https://github.com/microsoft/qlib/assets/8296331/38fef624-3458-4654-8c53-d6e3ba81f99f)
  
  ![image](https://github.com/microsoft/qlib/assets/8296331/31ad2e3b-36c6-4832-8431-532a4440f9e3)
  
  
  ## Environment
  
  **Note**: User could run `cd scripts && python collect_info.py all` under project directory to get system information
  and paste them here directly.
  
  ```
  Linux
  x86_64
  Linux-5.15.90.1-microsoft-standard-WSL2-x86_64-with-glibc2.35
  #1 SMP Fri Jan 27 02:56:13 UTC 2023
  
  Python version: 3.8.16 (default, Dec  7 2022, 01:12:06)  [GCC 11.3.0]
  
  Qlib version: 0.9.1.99
  numpy==1.23.5
  pandas==1.5.3
  scipy==1.10.1
  requests==2.31.0
  sacred==0.8.4
  python-socketio==5.8.0
  redis==4.5.5
  python-redis-lock==4.0.0
  schedule==1.2.0
  cvxpy==1.3.1
  hyperopt==0.1.2
  fire==0.5.0
  statsmodels==0.14.0
  xlrd==2.0.1
  plotly==5.15.0
  matplotlib==3.7.1
  tables==3.8.0
  pyyaml==6.0
  mlflow==1.30.0
  tqdm==4.65.0
  loguru==0.7.0
  lightgbm==3.3.5
  tornado==6.3.2
  joblib==1.2.0
  fire==0.5.0
  ruamel.yaml==0.17.31
  ```
  
  ## Additional Notes
  
  <!-- Add any other information about the problem here. -->
  