Add .prettierrc.json and refactor test files for improved formatting consistency:

- Introduced `.prettierrc.json` to enforce consistent code formatting across the project.
- Updated unit and e2e test files to address formatting issues, improve readability, and ensure alignment with the new Prettier configuration.

tests/unit/department-modules-setup-self-serve.spec.js

@@ -3,10 +3,7 @@ import { join } from "node:path";
 import { describe, expect, it } from "vitest";
 
 const source = readFileSync(
-  join(
-    process.cwd(),
-    "src/views/dashboards/superUserDashboard/department/modules/DepartmentModulesSetup.vue"
-  ),
+  join(process.cwd(), "src/views/dashboards/superUserDashboard/department/modules/DepartmentModulesSetup.vue"),
   "utf8"
 );
 
@@ -19,8 +16,8 @@ describe("DepartmentModulesSetup self-serve management regression", () => {
   });
 
   it("renders a dedicated self-serve module switch in setup UI", () => {
-    expect(source).toContain("subtitle=\"Selvvask\"");
-    expect(source).toContain("title=\"Selvvask\"");
+    expect(source).toContain('subtitle="Selvvask"');
+    expect(source).toContain('title="Selvvask"');
     expect(source).toContain("Aktiver selvvask i denne afdeling.");
   });
 });