Login failed for 2FA enabled account.

## Description of the problem
Can't login to the account which have 2FA enabled. Login works fine with the account which doesn't have 2FA enabled.

## Code I'm using:

```
def login_logout():
cookies = {}
try:
# Load the session cookies
if os.path.isfile('session.json'):
with open('session.json', 'r') as f:
cookies = json.load(f)
except:
os.remove('session.json')
# If it fails, never mind, we'll just login again
# client = CustomClient(email, password, max_tries=1)
if((not cookies) != True):
client = CustomClient(email, password, session_cookies=cookies, user_agent=user_agent, max_tries=1)
else:
client = CustomClient(email, password, user_agent=user_agent, max_tries=1)

with open('session.json', 'w') as f:
json.dump(client.getSession(), f)

print("\nProgram Started!\n")
client.listen()
```

# Error I'm getting

```
Traceback (most recent call last):
File "C:\Users\USERNAME\AppData\Local\Programs\Python\Python36\lib\site-pa
ckages\fbchat\_client.py", line 175, in setSession
self._state = State.from_cookies(session_cookies, user_agent=user_agent)
File "C:\Users\USERNAME\AppData\Local\Programs\Python\Python36\lib\site-pa
ckages\fbchat\_state.py", line 208, in from_cookies
return cls.from_session(session=session)
File "C:\Users\USERNAME\AppData\Local\Programs\Python\Python36\lib\site-pa
ckages\fbchat\_state.py", line 186, in from_session
fb_dtsg = FB_DTSG_REGEX.search(r.text).group(1)
AttributeError: 'NoneType' object has no attribute 'group'
```

## Environment information
- Python version 3.6.8
- `fbchat` version 1.9.6