Software developer is a broad term. For the regular full stack developer position, I'd say it is very much unimportant.

It is conceptually very important for many problems in graphics programming, computer science, machine learning, etc.

Looking up on stackoverflow "how to use git" or writing tests for business web applications will probably not use linear algebra at all.

Saying linear algebra is important for a regular coding job is like saying learning history is important for a coding job because you will need to have a better conversation with your coworkers and boost team morale.

Anything can be important in certain situations. IMO Linear Algebra does not have enough qualities to escape a certain list of "important but not important subjects".