ESLint: Add prefer-const rule

Require const declarations for variables that are never reassigned after
being declared. If a variable is never reassigned, using the const
declaration is better. const declaration tells readers, “this variable
is never reassigned,” reducing cognitive load and improving
maintainability.

src/test/Components/CreateImageWizard/CreateImageWizard.test.js

@@ -1518,7 +1518,7 @@ describe('Click through all steps', () => {
     expect(within(revtbody).getAllByRole('row')).toHaveLength(3);
 
     // mock the backend API
-    let ids = [];
+    const ids = [];
     const composeImage = jest
       .spyOn(api, 'composeImage')
       .mockImplementation((body) => {