fix: item spawning spells with no min/max damage

[casswedson]

Summary

None

Purpose of change

if a spell with the effect spawn_item does not have a defined min/max damage it will not spawn anything at any level (given it doesn't have something like damage increment)

setting the values manually just makes sense, just in case, so it always spawns something at level 1

scraped a bunch of data in search of spells that spawn items and do not have min/max damage defined, there were some

purpose of change:
how dare you make my favorite spell repelling arc useless as it does not spawn anything >:(

Describe the solution

Describe alternatives you've considered

Testing

Additional context

[mqrause]

how dare you make my favorite spell repelling arc useless as it does not spawn anything >:(

Oops, that's an unintended side effect of #64600. Instead of adding damage to all spells a small fix for this loop might be the better solution.

Cataclysm-DDA/src/magic_spell_effect.cpp

Line 1071 in e9ab834

for( int i = 0; i < sp.damage( caster ); i++ ) {