Astra DB connectors: switch out video embed link (#376)

Author: Paul-Cornell

snippets/general-shared-text/astradb.mdx

@@ -1,7 +1,7 @@
 <iframe
 width="560"
 height="315"
-src="https://www.youtube.com/embed/kupQrnCQjPw"
+src="https://www.youtube.com/embed/PMs1iwL52aM"
 title="YouTube video player"
 frameborder="0"
 allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture"