This question already has an answer here:
No, and in fact it stopped being part of the official canon universe prior to the canon purge of April 2014 with the production of the new Star Wars: The Clone Wars TV series which dealt with many of the same events.
Tartakovsky himself discussed this issue in an interview with TheForce.net in September 2012
Speaking of your version of "Clone Wars," does it bother you that there's another one and that the one you did seems to no longer be canon?
Yeah. I mean, you know, of course it bothers me. But, you know, it's George's characters. It's his world and he has to do what he has to do. And the new ones are totally inspired by what we did: A lot of the same character designs and stuff.
Does that part bother you, too?
No, again, it's not my characters, so he can do whatever he wants. And the story was also that I was going to do it. I was going to go to Lucas and be their John Lasseter-type of person and do a feature and supervise the "Star Wars" television show. And things kind of fell apart, blah blah blah. But, yeah, I'm super proud of what we did. And I felt like we did a justice to "Star Wars" and as a fan.
I mean, people haven't forgotten them, even though we are supposed to.
That's the one thing that is kind of weird that he just wants to wipe it off. Because we used to be in the encyclopedias, some of the characters that we created. And now they're gone. And you can't get the DVD and all of this other stuff. And it's like, whatever. What are you going to do, right? It existed.
But it feels like its been thrown on the scrapheap with the Holiday Special.
I think George is brilliant. And I think he just wants to ... I don't know the reasoning, exactly. But from any sense that I can make out of it, he just wants it to be clean. But there's so much fiction that's out with "Star Wars," I don't think it would matter."