Disable "Fetch Local" AI context feature in dashboard

- The implementation assumes you're in the CS, using things like `document.body` to get live page content to supply as context to the LLMs. That's going to give bad data in the dashboard, thus better to disable until we can add an implementation which works there

src/sidebar/annotations-sidebar/components/AnnotationsSidebar.tsx

@@ -2047,6 +2047,9 @@ export class AnnotationsSidebar extends React.Component<
                             />
                         )
                     }}
+                    omitLocalContentFeature={
+                        this.props.sidebarContext === 'dashboard'
+                    }
                 />
             </AISidebarContainer>
         )