Remove IIFEs from stat_graph_contributors_graph.js
What does this MR do?
Replaces the Immediately Invoked Function Expressions from javascript in the contributors stat graphing feature as requested in &2074 (closed) -> #34613 (closed)
Replaces the Immediately Invoked Function Expressions from javascript in the contributors stat graphing feature as requested in &2074 (closed) -> #34613 (closed)