Add SRI to devicepx-jetpack.js

#### Is your feature request related to a problem? Please describe.

The file `devicepx-jetpack.js` should be loaded with SubResource Integrity.

#### Describe the solution you'd like

#### Describe alternatives you've considered
[SRI is well supported in major browsers](https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity) and has no negative impact on legacy browsers.

Adding SRI means that if the CDN is compromised, or the code is maliciously altered, browsers will not execute it.

#### Additional context

As per #10027, the CDN supports CORS.

Locate where devicepx-jetpack.js is loaded and start by checking that generated script tag against the issue's SRI and crossorigin example. Done means the file is loaded with the requested integrity protection and cross-origin setting, with the existing loading behavior preserved.

Written by the indexing model from the issue text.