[FEATURE] Disable Pre-loading for the Reusable Blocks (Synced Patterns)

[mslinnea]

Description

WordPress pre-loads all Reusable Blocks (Synced Patterns) on the edit post screen, site editor, and widget screen. For sites with hundreds of blocks, this is a lot of processing overhead, as the_content and all other filters run on these blocks. Disabling this behavior make the editing experience faster and less fragile for sites with a large number of blocks.

Use Case

As a developer, I want to remove the preloading of blocks to increase performance on sites with a large number of blocks.

[mslinnea]

Feature added in #92