Merge pull request #472 from plotly/sept30-webinar-ad

Update sidebar ad to Sept 30 webinar

Author: red-patience

_includes/layouts/webinar_plug.html

@@ -1,5 +1,5 @@
 
-   <a href="https://plotly.com/webinars/plotly-studio-projects/?source=graphing_libraries&medium=documentation&campaign=plotly-studio-projects-16sept2026&content=sidebar" target="_blank">
-     <img src="https://images.prismic.io/plotly-marketing-website-2/oXGLlCJWomRqcLDk_plotly-studio-projects.jpg?auto=format,compress"
-     style="width: 200px; height: 200px; position: fixed; bottom: 10px; left: 50px" alt="Sign up for the upcoming webinar: One Workspace for Every Session with Plotly Studio Projects">
+   <a href="https://plotly.com/webinars/claude-plotly-cloud/?source=graphing_libraries&medium=documentation&campaign=claude-plotly-cloud-30sept2026&content=sidebar" target="_blank">
+     <img src="https://images.prismic.io/plotly-marketing-website-2/tlG53ksFIxRursOc_claude-connector-and-major-upgrades-to-plotly-py-and-plotly-js.jpg?auto=format,compress"
+     style="width: 200px; height: 200px; position: fixed; bottom: 10px; left: 50px" alt="Sign up for the upcoming webinar: Claude Connector and Major Upgrades to Plotly.py and Plotly.js">
    </a>