refactor: 💡 convert brokered cred IDs array to simple attribute (#1259)

* refactor: 💡 convert brokered cred IDs array to simple attribute

* fix: 🐛 missing test assertion

* fix: 🐛 simplify computed

* refactor: 💡 convert host sources array to simple attribute (#1260)

* refactor: 💡 convert host source IDs array to simple attribute

* fix: 🐛 host source tests

* Refactor role fragment arrays (#1262)

* refactor: 💡 convert grant strings to regular attribute

* refactor: 💡 convert principals array to simple attribute

* Update ui/admin/app/routes/scopes/scope/roles/role.js

Co-authored-by: Zhihe Li <zhihe.li@hashicorp.com>

Co-authored-by: Zhihe Li <zhihe.li@hashicorp.com>

Co-authored-by: Zhihe Li <zhihe.li@hashicorp.com>

* fix: 🐛 remove unused import

Co-authored-by: Zhihe Li <zhihe.li@hashicorp.com>

addons/api/addon/transforms/principal-array.js

@@ -0,0 +1,21 @@
+import Transform from '@ember-data/serializer/transform';
+
+export default class PrincipalArrayTransform extends Transform {
+  deserialize(serialized) {
+    const stringValues = serialized || [];
+    return stringValues.map(({ id: principal_id, scope_id, type }) => ({
+      principal_id,
+      scope_id,
+      type,
+    }));
+  }
+
+  serialize(deserialized) {
+    const strings = deserialized || [];
+    return strings.map(({ principal_id: id, scope_id, type }) => ({
+      id,
+      scope_id,
+      type,
+    }));
+  }
+}