fix: use put instead of post and improve var naming

backend/src/server/routes/v1/external-group-org-role-mapping-router.ts

@@ -38,7 +38,7 @@ export const registerExternalGroupOrgRoleMappingRouter = async (server: FastifyZ
 
   // update mappings for current org
   server.route({
-    method: "POST", // using post since this endpoint creates, updates and deletes mappings
+    method: "PUT", // using put since this endpoint creates, updates and deletes mappings
     url: "/",
     config: {
       rateLimit: writeLimit

backend/src/services/org/org-role-fns.ts

@@ -5,8 +5,7 @@ import { TOrgRoleDALFactory } from "@app/services/org/org-role-dal";
 
 const RESERVED_ORG_ROLE_SLUGS = Object.values(OrgMembershipRole).filter((role) => role !== "custom");
 
-export const isCustomOrgRole = (membershipSlug: string) =>
-  !RESERVED_ORG_ROLE_SLUGS.includes(membershipSlug as OrgMembershipRole);
+export const isCustomOrgRole = (roleSlug: string) => !RESERVED_ORG_ROLE_SLUGS.includes(roleSlug as OrgMembershipRole);
 
 // this is only for updating an org
 export const getDefaultOrgMembershipRoleForUpdateOrg = async ({