Exception when preparing an amplicon library with a 384 well plate

In my test environment, I have amplicon 384-well plates. It appears that the prepare amplicon libraries page is not presently validating that the primer plates have the same number of wells. I'm not sure if we ever want to do 384 well amplicon plates, but we may want to have validation here to disallow the user from doing something they shouldn't be able to do.

I can't remember if this is a duplicate or not -- it felt familiar but I didn't see an issue when flipping through.


```bash
AN ERROR HAS OCCURED!
Please copy the following into an issue in our github repository

Error
list index out of range

Traceback
Traceback (most recent call last):
File "/Users/dtmcdonald/miniconda3/envs/labcontrol/lib/python3.7/site-packages/tornado/web.py", line 1697, in _execute result = method(*self.path_args, **self.path_kwargs)
File "/Users/dtmcdonald/miniconda3/envs/labcontrol/lib/python3.7/site-packages/tornado/web.py", line 3174, in wrapper return method(self, *args, **kwargs)
File "/Users/dtmcdonald/ResearchWork/software/labman/labcontrol/gui/handlers/process_handlers/library_prep_16s_process.py", line 88, in post for pid, pn, pp, ep, ep300, ep50, mm, w in json_decode(plates_info)
File "/Users/dtmcdonald/ResearchWork/software/labman/labcontrol/gui/handlers/process_handlers/library_prep_16s_process.py", line 88, in for pid, pn, pp, ep, ep300, ep50, mm, w in json_decode(plates_info)
File "/Users/dtmcdonald/ResearchWork/software/labman/labcontrol/db/process.py", line 933, in create primer_layout[i][j].composition)
IndexError: list index out of range
```