Client creation sends invalid scope data

[Elleo]

Currently when calling createApplication scopes are converted to a list, which is then json encoded (e.g. ["read", "write", "push"]). However, Mastodon expects a space-delimited string of scopes ("read write push"). The Mastodon server then just assigns the default "read" scope to the application. Attempts to authenticate with more scopes than "read" result in the Mastodon server responding with: "The requested scope is invalid, unknown, or malformed."

[github-actions]

Thanks for your contribution! :)