Enhancement: Jetpack Like block - add option to select a post ID

### Impacted plugin

Jetpack

### What

It would be useful if the Jetpack Like button had an option to select a post ID for which the like button is rendered. Currently, the Like button automatically associates with the global post ID of the current page. However, there are scenarios where the necessity arises to link the Like button with a different post ID

### How

The proposed modification entails introducing a post selector, enabling users to choose a specific post for which the like button would be displayed. If this option is left unselected, the current global $post will be used, maintaining the default behavior.

Start by locating the Jetpack Like block and its current use of the global $post. Trace how the block chooses the associated post, then verify that an optional post selection uses the chosen ID while leaving the unselected case tied to the current page.

Written by the indexing model from the issue text.