fix: remove rebrand experiment from authn (#1187)

Description:
Remove rebrand experiment code from Authn
VAN-1858

src/base-container/data/constants.js

@@ -1,4 +0,0 @@
-const IMAGE_LAYOUT = 'image-layout';
-const DEFAULT_LAYOUT = 'default-layout';
-
-export { DEFAULT_LAYOUT, IMAGE_LAYOUT };

src/base-container/index.jsx

@@ -1,4 +1,4 @@
-import React, { useEffect, useState } from 'react';
+import React from 'react';
 
 import { getConfig } from '@edx/frontend-platform';
 import { breakpoints } from '@openedx/paragon';
@@ -11,28 +11,11 @@ import {
   ImageExtraSmallLayout, ImageLargeLayout, ImageMediumLayout, ImageSmallLayout,
 } from './components/image-layout';
 import { AuthLargeLayout, AuthMediumLayout, AuthSmallLayout } from './components/welcome-page-layout';
-import { DEFAULT_LAYOUT, IMAGE_LAYOUT } from './data/constants';
 
 const BaseContainer = ({ children, showWelcomeBanner, fullName }) => {
-  const [baseContainerVersion, setBaseContainerVersion] = useState(DEFAULT_LAYOUT);
   const enableImageLayout = getConfig().ENABLE_IMAGE_LAYOUT;
 
-  useEffect(() => {
-    const initRebrandExperiment = () => {
-      if (window.experiments?.rebrandExperiment) {
-        setBaseContainerVersion(window.experiments?.rebrandExperiment?.variation);
-      } else {
-        window.experiments = window.experiments || {};
-        window.experiments.rebrandExperiment = {};
-        window.experiments.rebrandExperiment.handleLoaded = () => {
-          setBaseContainerVersion(window.experiments?.rebrandExperiment?.variation);
-        };
-      }
-    };
-    initRebrandExperiment();
-  }, []);
-
-  if (baseContainerVersion === IMAGE_LAYOUT || enableImageLayout) {
+  if (enableImageLayout) {
     return (
       <div className="layout">
         <MediaQuery maxWidth={breakpoints.extraSmall.maxWidth - 1}>

src/base-container/tests/BaseContainer.test.jsx

@@ -25,23 +25,6 @@ describe('Base component tests', () => {
     expect(container.querySelector('.large-screen-svg-primary')).toBeDefined();
   });
 
-  it('[experiment] should show image layout for treatment group', () => {
-    window.experiments = {
-      rebrandExperiment: {
-        variation: 'image-layout',
-      },
-    };
-
-    const { container } = render(
-      <IntlProvider locale="en">
-        <BaseContainer />
-      </IntlProvider>,
-      LargeScreen,
-    );
-
-    expect(container.querySelector('.banner__image')).toBeDefined();
-  });
-
   it('renders Image layout when ENABLE_IMAGE_LAYOUT configuration is enabled', () => {
     mergeConfig({
       ENABLE_IMAGE_LAYOUT: true,