Handling external_alert FRAs with underscores in name

[physics-png]

Right now, as it is written we are unable to run FRAs when we put underscores in the FRA name. We should either print a warning and prevent the code from running OR have the code automatically fix this:

latex was not able to process the following string:
b'FRB 20121102A_2026_July'

Here is the full report generated by latex:
latex: /cvmfs/icecube.opensciencegrid.org/py3-v4.1.0/RHEL_7_x86_64/lib/libtiff.so.5: no version information available (required by /lib64/libpoppler.so.46)
This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013)
 restricted \write18 enabled.
entering extended mode```