Update sources.py to fix energy columns in bolide dataframe

[VKeff]

Example of Error:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
[<ipython-input-2-5d8bc327a36c>](https://localhost:8080/#) in <cell line: 0>()
----> 1 bdf = BolideDataFrame(source='glm')

1 frames
[/usr/local/lib/python3.11/dist-packages/bolides/bdf.py](https://localhost:8080/#) in __init__(self, *args, **kwargs)
     99         if source in ['website', 'glm']:
    100             source = 'glm'
--> 101             init_gdf = glm_website()
    102 
    103         elif source == 'usg':

[/usr/local/lib/python3.11/dist-packages/bolides/sources.py](https://localhost:8080/#) in glm_website()
     33                 e_g16 += energy
     34             if platform == 'G17':
---> 35                 e_g17 += energy
     36         if e_g16 == 0:
     37             e_g16 = np.nan

TypeError: unsupported operand type(s) for +=: 'int' and 'NoneType' 

Proposed Solution:
Under energy = at['energy'], add the following:
if energy==None: energy=0

This solution has worked in tandem with the previous sources.py issue's datetime solution and allows all NaN/Nonetype energies to be written as 0. This facilitates accessing the energy data but may skew statistical analysis so use with caution.