amp-script touchstart, touchmove, touchend do not register as interaction add Feature

## New Feature

Existing code:
https://github.com/ampproject/amphtml/blob/d2999e1b4776c438059695d7d525f2e036154e28/extensions/amp-script/0.1/user-activation-tracker.js#L18-L28

New Code:
```javascript
const ACTIVATION_EVENTS = [
'touchstart',
'touchmove',
'touchend',
'change',
'click',
'dblclick',
'input',
'keypress',
'submit',
'keydown',
];
```

## Problem

`amp-script` will block mutation, because `touchstart`, `touchmove`, `touchend` do not count as interaction.

This makes it impossible to implement things that open/close by swipe, outside of a fixed layout.

## Additional context

Should I open a PR with the suggested changes?

Start with extensions/amp-script/0.1/user-activation-tracker.js at the linked ACTIVATION_EVENTS definition and inspect how those events are used to permit mutations. Add touchstart, touchmove, and touchend as activation events, then verify that swipe-related interactions are no longer blocked by amp-script mutation restrictions.

Written by the indexing model from the issue text.