🚮 Sweep experiments older than 2023-03-01

Sweep experiments last flipped globally up to 2023-03-01:

- (2021-01-20, a9e2778) `adsense-ad-size-optimization`: 1
- (2020-11-19, cac0248) `amp-accordion-display-locking`: 1
- (2020-08-14, 77ced1d) `expand-json-targeting`: 1
- (2021-01-27, b738789) `visibility-trigger-improvements`: 1
- (2021-03-05, 77127c7) `disable-a4a-non-sd`: 1
- (2021-03-12, 1b7583d) `tcf-post-message-proxy-api`: 1
- (2021-03-17, db781bd) `amp-consent-granular-consent`: 1
- (2021-03-23, 1115f6c) `amp-cid-backup`: 1

---

### Cleanup issues

Close these once they've been addressed and this PR has been merged:

- [ ] `adsense-ad-size-optimization`: ampproject#24165
- [ ] `visibility-trigger-improvements`: ampproject#26823
- [ ] `amp-cid-backup`: ampproject#29484

---

### ⚠️ Javascript source files require intervention

The following may contain errors and/or require intervention to remove superfluous conditionals:

- [ ] `extensions/amp-a4a/0.1/amp-a4a.js`
- [ ] `extensions/amp-a4a/0.1/test/test-amp-a4a.js`
- [ ] `extensions/amp-accordion/0.1/amp-accordion.js`
- [ ] `extensions/amp-accordion/0.1/test/test-amp-accordion.js`
- [ ] `extensions/amp-accordion/1.0/amp-accordion.js`
- [ ] `extensions/amp-accordion/1.0/test/test-amp-accordion.js`
- [ ] `extensions/amp-analytics/0.1/analytics-root.js`
- [ ] `extensions/amp-analytics/0.1/test/test-analytics-root.js`
- [ ] `extensions/amp-analytics/0.1/test/test-events.js`
- [ ] `extensions/amp-consent/0.1/amp-consent.js`
- [ ] `extensions/amp-consent/0.1/consent-ui.js`
- [ ] `extensions/amp-consent/0.1/test/test-amp-consent.js`
- [ ] `extensions/amp-consent/0.1/test/test-consent-ui.js`
- [ ] `src/custom-element.js`
- [ ] `src/service/cid-impl.js`
- [ ] `test/unit/test-custom-element.js`

Refer to the removal guide for [suggestions on handling these modified Javascript files.](https://github.com/ampproject/amphtml/blob/master/build-system/tasks/sweep-experiments/README.md#followup)

---

### ⚠️ HTML files may still contain references

The following HTML files contain references to experiment names which may be stale and should be manually removed:

- [ ] `examples/accordion.amp.html`
- [ ] `examples/amp-consent/amp-consent-3p-postmessage.html`
- [ ] `test/manual/amp-analytics/amp-analytics-multi-selector.html`
- [ ] `test/manual/amp-consent/amp-consent-granular-consent.html`

Refer to the removal guide for [suggestions on handling these HTML files.](https://github.com/ampproject/amphtml/blob/master/build-system/tasks/sweep-experiments/README.md#followup:html)