fix domination "peaceful" bases

[ABCxFF]

Why:

Domination bases that inflict no damage were auto killing bullets

Summarize what's being changed (include any screenshots, code, or other media if available):

checks if the object is a base with killability before killing bullets

Confirm the following:

• [x] I have tested these changes (by compiling, running, and playing) and have seen no differences in gameplay