revert: "docs: add coder registry link to docs sidebar" (coder#18837)

Author: matifali

docs/manifest.json

@@ -1767,11 +1767,6 @@
 					]
 				}
 			]
-		},
-		{
-			"title": "Coder Registry",
-			"description": "A collection of Templates and Modules used to create and extend Coder workspaces.",
-			"path": "./registry/index.md"
 		}
 	]
 }