Clone Repo script produces excessive project search requests when trying to generate its parameters

When trying to load the page for the Clone Repo built-in script in a project-level context, ScriptRunner has to check which repos are in projects that the current user has the right to administrate. For each repo in turn, it does this by searching for all projects where the user has admin permissions and seeing if that repo's project is among them. This represents a lot of unnecessarily replicated computation and performs badly when there are large numbers of repos and projects.