Embed Block: Add support for x.com links

[cuemarie]

What problem does this address?

Tying to use the https://x.com URL to embed tweets results in a text link only. Swapping the x.com for twitter.com does work to embed the tweet.

Originally requested here: Automattic/wp-calypso#81116

What is your proposed solution?

Add support for both URL versions to be embedded by the Embed block.

[BrookeDot]

Related Core Trac ticket: https://core.trac.wordpress.org/ticket/59142

[fluiddot]

The Embed block relies on the oEmbed endpoint provided by WordPress. I checked the oEmbed implementation and seems that x.com URLs are not included, so embeds using that URL won’t be resolved using the Twitter/X oEmbed service (https://publish.twitter.com/oembed). I also checked the Twitter/X API for embeds, as well as the Twitter embed tool, and surprisingly it doesn’t resolve either using x.com URLs 🤔. I tried generating the embed code directly from a Tweet and it uses the twitter.com domain, so seems that for embeds we should still use that domain.

It’s not clear whether the Twitter oEmbed API will support x.com URLs, so in the meantime we could manually change the domain to twitter.com when requesting the embed as a workaround. Eventually, the x.com URLs should be supported in the WordPress oEmbed functionality.

[fluiddot]

Following this comment, I opened #54876 with the shared proposal.