fix: #9019, add missing lang strings

public/language/en-GB/error.json

@@ -109,6 +109,8 @@
 	"cant-remove-last-admin": "You are the only administrator. Add another user as an administrator before removing yourself as admin",
 	"cant-delete-admin": "Remove administrator privileges from this account before attempting to delete it.",
 
+	"already-deleting": "Already deleting",
+
 	"invalid-image": "Invalid image",
 	"invalid-image-type": "Invalid image type. Allowed types are: %1",
 	"invalid-image-extension": "Invalid image extension",

src/api/users.js

@@ -247,7 +247,7 @@ async function processDeletion({ uid, method, password, caller }) {
 	} else if (!isSelf && !isAdmin) {
 		throw new Error('[[error:no-privileges]]');
 	} else if (isTargetAdmin) {
-		throw new Error('[[error:cant-delete-other-admins]]');
+		throw new Error('[[error:cant-delete-admin]');
 	}
 
 	// Privilege checks -- only deleteAccount is available for non-admins