Unsure why they would join a shooting war.
Perhaps aiding and abetting? But an act of war, no.
Why would you believe this? The last time they didn't like their government, they replaced it with the current government. Even the Ayatollah was pissed off that they mistakenly shot down a plane full of Iranians; they weren't about to curb the relatively limited public demonstrations that agreed with him on that topic.
Oh, let me guess... you learned of the average Iranian's great political discontent from the USA war media. "Wishful thinking disguised as reporting" leads to wishful thinking in place of analysis.
Russia won't, neither will most African nations.
There won't be a war anyhow.