fix(marketplace): use existing i18n key for missing marketplace-installed mode; remove added en locale key to satisfy translation check

Author: matt-rudolph

src/i18n/locales/en/marketplace.json

@@ -65,8 +65,5 @@
 		"removing": "Removing item: \"{{itemName}}\"",
 		"removeSuccess": "\"{{itemName}}\" removed successfully",
 		"removeError": "Failed to remove \"{{itemName}}\": {{errorMessage}}"
-	},
-	"errors": {
-		"scopedDeletionNotSupported": "Scoped deletion is not supported in this version. Please update Roo Code to the latest version and try again."
 	}
 }

src/services/marketplace/SimpleInstaller.ts

@@ -351,7 +351,7 @@ export class SimpleInstaller {
 			await (this.customModesManager as any).deleteCustomModeForSource(modeSlug, target, true)
 		} else {
 			// Scoped deletion not supported in this version
-			throw new Error(t("marketplace:errors.scopedDeletionNotSupported"))
+			throw new Error("Scoped deletion is not supported in this version")
 		}
 	}