Clean up as per review comments

Signed-off-by: Andy Caruso <macaruso@gmail.com>

plugins/auth-backend/src/identity/TokenFactory.test.ts

@@ -24,7 +24,10 @@ const logger = getVoidLogger();
 
 function jwtKid(jwt: string): string {
   const header = decodeProtectedHeader(jwt);
-  return header.kid ?? '';
+  if (!header.kid) {
+    throw new Error('JWT Header did not contain a key ID (kid)');
+  }
+  return header.kid;
 }
 
 const entityRef = stringifyEntityRef({

plugins/auth-backend/src/providers/aws-alb/provider.ts

@@ -44,11 +44,6 @@ type Options = {
   resolverContext: AuthResolverContext;
 };
 
-export const getJWTHeaders = (input: string): AwsAlbHeaders => {
-  const encoded = input.split('.')[0];
-  return JSON.parse(Buffer.from(encoded, 'base64').toString('utf8'));
-};
-
 export type AwsAlbHeaders = {
   alg: string;
   kid: string;