fix(amazonq): AB users with overridden customization can restore the default customization aws#6450

## Problem
Users that are part of an AB group that have a customization override
can't go back to the default customization. This was the original
intention but has been relaxed after feedback.

## Solution
Update setSelectedCustomization to no longer check if the user is trying
to switch back to the default customization.

Author: spfink

packages/amazonq/.changes/next-release/Bug Fix-1d7e776d-333a-4f39-a8e6-29ea2ecb19c9.json

@@ -0,0 +1,4 @@
+{
+	"type": "Bug Fix",
+	"description": "Allow AB users with an overridden customization to go back to the default customization"
+}

packages/core/src/codewhisperer/util/customizationUtil.ts

@@ -113,7 +113,7 @@ export const getSelectedCustomization = (): Customization => {
     )
     const selectedCustomization = selectedCustomizationArr[AuthUtil.instance.conn.label]
 
-    if (selectedCustomization && selectedCustomization.name !== baseCustomization.name) {
+    if (selectedCustomization && selectedCustomization.name !== '') {
         return selectedCustomization
     } else {
         const customizationFeature = FeatureConfigProvider.getFeature(Features.customizationArnOverride)

packages/core/src/test/amazonq/customizationUtil.test.ts

@@ -85,7 +85,10 @@ describe('CodeWhisperer-customizationUtils', function () {
     it('Returns AB customization', async function () {
         sinon.stub(AuthUtil.instance, 'isValidEnterpriseSsoInUse').returns(true)
 
-        await setSelectedCustomization(baseCustomization)
+        await setSelectedCustomization({
+            arn: '',
+            name: '',
+        })
 
         const returnedCustomization = getSelectedCustomization()