ci: Update circleci config to correctly run mv3 e2e tests (#24704)

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## **Description**

This ensures that `ENABLE_MV3=true` is correctly set for all tests run
within the `test-e2e-chrome-mv3` job, and it ensures test results are
stored on circleci (in the case of failures).

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## **Manual testing steps**

When grouped with all the other e2e fixes, e2e tests should pass. [TODO:
add list of all PRs here]

## **Pre-merge author checklist**

- [ ] I’ve followed [MetaMask Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've completed the PR template to the best of my ability
- [ ] I’ve included tests if applicable
- [ ] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

.circleci/config.yml

@@ -1007,14 +1007,16 @@ jobs:
       - run:
           name: test:e2e:chrome
           command: |
-            if .circleci/scripts/test-run-e2e.sh
-            then
-              timeout 20m yarn test:e2e:chrome --retries 2 || echo "Temporarily suppressing MV3 e2e test failures"
+            export ENABLE_MV3=true
+            if .circleci/scripts/test-run-e2e.sh; then
+              timeout 20m yarn test:e2e:chrome --retries 2
             fi
           no_output_timeout: 5m
       - store_artifacts:
           path: test-artifacts
           destination: test-artifacts
+      - store_test_results:
+                path: test/test-results/e2e
 
   test-e2e-chrome-rpc:
     executor: node-browsers-medium