Python Pandas- Dataframe from Nested JSON

I am trying to normalize a nested JSON file in pandas.
I am unable to get the ab_id column in the beginning as observed in the current output screenshot.
Additionally, since if I remove record prefix from my code, I am seeing an error and if I add it it generates a couple of columns which are empty.

The current and expected output is attached in the screenshot below:

Code used currently:

df=pd.json_normalize(data=response['val'],record_path=['activity'],meta=['msn','iis','ica','iada'],errors='ignore', record_prefix='_')

JSON file:

{
   "id":"ijewiofn23441312223",
   "val":[
      {
         "ab_id":"ab_123",
         "activity":[
            {
               "msn":"acpfile_source_conn",
               "iia":true,
               "ica":false,
               "iada":false
            },
            {
               "msn":"adefile_source_conn",
               "iia":true,
               "ica":false,
               "iada":false
            }
            }
         ]
      },
      {
         "ab_id":"ab_421",
         "activity":[
            {
               "msn":"adbfile_source_conn",
               "iia":true,
               "ica":true,
               "iada":false
            },
            {
               "msn":"aile_source_conn",
               "iia":true,
               "ica":false,
               "iada":false
            }
            }
         ]
      }
   ]
}

Can someone please help out?
Thanks so much in advance.

import pandas as pd
from pandas import json_normalize

data = {
    "id": "ijewiofn23441312223",
    "val": [
        {
            "ab_id": "ab_123",
            "activity": [
                {
                    "msn": "acpfile_source_conn",
                    "iia": True,
                    "ica": False,
                    "iada": False
                },
                {
                    "msn": "adefile_source_conn",
                    "iia": True,
                    "ica": False,
                    "iada": False
                }
            ]
        },
        {
            "ab_id": "ab_421",
            "activity": [
                {
                    "msn": "adbfile_source_conn",
                    "iia": True,
                    "ica": True,
                    "iada": False
                },
                {
                    "msn": "aile_source_conn",
                    "iia": True,
                    "ica": False,
                    "iada": False
                }
            ]
        }
    ]
}
df = pd.json_normalize(data['val'], record_path=['activity'], meta=['ab_id'])
df = df[['ab_id'] + [col for col in df.columns if col != 'ab_id']]
df.columns = ['id'] + df.columns[1:].tolist()

print(df)