test: Implement the structure of mocking appConfig options

packages/backend/test/setup/set-mock-config.ts

@@ -0,0 +1,13 @@
+export const mockConfigState = {
+  isCloud: false,
+};
+
+export const resetMockConfig = () => {
+  for (const key in mockConfigState) {
+    delete (mockConfigState as any)[key];
+  }
+};
+
+export const setMockConfig = (config: Partial<typeof mockConfigState>) => {
+  Object.assign(mockConfigState, config);
+};