fix(organization): organization with no members error (#2999)

* fix: handle empty userIds in getOrgAdapter to prevent errors

* refactor: remove unnecessary whitespace in getOrgAdapter function

* refactor: simplify user fetching logic in getOrgAdapter function

---------

Co-authored-by: Sean Luca Krüger <mail@seanlucakrueger.de>

packages/better-auth/src/plugins/organization/adapter.ts

@@ -350,11 +350,14 @@ export const getOrgAdapter = (
 			if (!org) return null;
 
 			const userIds = members.map((member) => member.userId);
-			const users = await adapter.findMany<User>({
-				model: "user",
-				where: [{ field: "id", value: userIds, operator: "in" }],
-				limit: options?.membershipLimit || 100,
-			});
+			const users =
+				userIds.length > 0
+					? await adapter.findMany<User>({
+							model: "user",
+							where: [{ field: "id", value: userIds, operator: "in" }],
+							limit: options?.membershipLimit || 100,
+						})
+					: [];
 
 			const userMap = new Map(users.map((user) => [user.id, user]));
 			const membersWithUsers = members.map((member) => {