fix(rum-explorer): empty entries in source or target

[kptdobe]

We now track LCP source and target. In some cases, no id or url can be determined thus we store the first character of the element outer HTML (might element determining what is the element). Problem: the HTML is not escaped and set as data attribute which corrupt the DOM.

Before:

• https://www.aem.live/tools/rum/explorer.html?domain=www.aem.live&filter=&view=week&metrics=all&checkpoint=cwv-lcp&domainkey=53A02890-F91F-428B-A870-A809B82D953E
• cwv-source facet contains empty entries

After:

• https://escape-html--helix-website--adobe.aem.live/tools/rum/explorer.html?domain=www.aem.live&filter=&view=week&metrics=all&checkpoint=cwv-lcp&domainkey=53A02890-F91F-428B-A870-A809B82D953E
• cwv-source facet contains html elements

Note: the escaping is added to all facets and might slow down the rendering. Probably non significantly. If needed and for performance improvements, we could escape only the source and target, not all facets.

[aem-code-sync[bot]]

Hello, I'm the AEM Code Sync Bot and I will run some actions to deploy your branch and validate page speed. In case there are problems, just click a checkbox below to rerun the respective action.

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Commits

* [7eace40](https://github.com/adobe/helix-website/commit/7eace40449f0118758e4be76e964c6cc02eb8405) :white_check_mark: (latest) * [0059c41](https://github.com/adobe/helix-website/commit/0059c414c82bceb945f1b5ef66a002c10a8b05b8) :white_check_mark: * [693637c](https://github.com/adobe/helix-website/commit/693637c7fcd8f292ed8cec676d037fd3f0619f4d) :white_check_mark:

[aem-code-sync[bot]]

Page	Scores	Audits	Google
/tools/rum/explorer.html?domain=www.aem.live&filter=&view=week&metrics=all&check point=cwv-lcp&domainkey=53A02890-F91F-428B-A870-A809B82D953E