Phoenix bugfix for undefined outputFormat (#1556)

Initialize outputFormats to the empty list

outputFormats is derived from sequencing language adaptation, but
starts out as undefined. This commit protects any code that assumes
it's always a list.

Co-authored-by: Matthew Dailis <[email protected]>

src/components/sequencing/SequenceEditor.svelte

@@ -84,7 +84,7 @@
   let editorSequenceDiv: HTMLDivElement;
   let editorSequenceView: EditorView;
   let menu: Menu;
-  let outputFormats: IOutputFormat[];
+  let outputFormats: IOutputFormat[] = [];
   let selectedNode: SyntaxNode | null;
   let selectedOutputFormat: IOutputFormat | undefined;
   let toggleSeqJsonPreview: boolean = false;