docs(api-keys): update API keys demo video

Swap in the new light/dark API keys demo videos.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: vasilev-alex

docs-mintlify/admin/account-billing/api-keys.mdx

@@ -10,8 +10,16 @@ Create and revoke API keys for your Cube organization.
   muted
   loop
   playsInline
-  className="w-full aspect-video rounded-xl"
-  src="https://lgo0ecceic.ucarecd.net/4f31a10c-c77f-4185-873c-d6893379d6ad/"
+  className="w-full aspect-video rounded-xl block dark:hidden"
+  src="https://ucarecdn.com/75100f27-d155-421b-9910-19afbb2fa9fd/abf7f59d-light.mp4"
+></video>
+<video
+  autoPlay
+  muted
+  loop
+  playsInline
+  className="w-full aspect-video rounded-xl hidden dark:block"
+  src="https://ucarecdn.com/aaa1eb9c-004d-417e-8c96-064ab0134ab1/523b2e1b-dark.mp4"
 ></video>
 
 ## Deployment scope