Could the reason I stopped having migraines be because I had a stroke?

That is a fascinating story - and there is probably a connection.  However, unfortunately, so little is known about the cause of migraines that I can't tell you for sure what science underlies your particular case.

It is known that people with migraines are at slightly higher chance than the general population to have a stroke, but what the relationship here was, I do not know.  Perhaps whatever center of brain was causing the migraines prior to the stroke was damaged, thereby stopping the cycle of migraines.  That is perhaps the first time I've heard of something good coming from a stroke!