I think it worked. I went to the Community Plan page and clicked "Get started free". I got a message saying:
You have an account with us
You're using [email] with another Microsoft service already. To finish signing up for Microsoft PowerApps, sign in with your existing password.
I clicked the "Sign in" button and got a message saying:
No need to sign up
You already have a license for Microsoft PowerApps.
I clicked "OK, got it", then got:
Hi Shane
We need some information to get you started with the PowerApps Community program.
I selected "Canada" under "Choose your country to begin" and clicked "Accept".
Shane.