Sorry but as long as you're living at home there is not much you can do, except for making the best out of a bad situation. Outside of being away as much as you can of course, because that's an option you also have.
It sucks your grandma is sick and not able to care for herself anymore. It probably why your parents chose to move her into the house in the first place. This wasn't done to annoy you and no doubt it's not easy on your parents either. Yet they probably also can't afford a care home as those are really expansive.
This means you'll have to live with her and the dog for a while. How long is hard to say of course, but find ways to deal as best you can. Taking your bad mood out on others will only make things worse. Such things have a cascading effect, before you know it everyone is in a shitty move.
Maybe you can take on the challenge to be a ray of sunshine no matter what happens around you? Happiness is a state of mind after all and you can practice that. Find the good in every situation, be mindful of others, practice compassion, resilience, do good deeds (like care for a stinky dog -who you can train or wash if needed), etc.
Or you can feel bad and stuck and all sorts of negative feelings about a situation you can't change. It's not going to be pretty but it's an option. If you can't change your grandma living with you, why not try to make it as pleasant as you can? Finding what works could be a nice journey or an exciting adventure, if you want it to be.