Build/Test Tools: Remove gutenberg:verify script on postinstall.

In [61458], a `postinstall` script was introduced that ensured the source code from the `gutenberg` repository was present before attempting to run the build script.

The WordPress.org Hosting Tests surfaced an edge case where the `postinstall` script was failing when `nodevenv` is used. Because it serves as a wrapper for Node.js, `NPM_CONFIG_PREFIX` is set to the virual envirnoment directory and not the actual project source directory.

This removes `gutenberg:verify` from `postinstall` entirely. `gutenberg:verify` is responsible for confirming that the `gutenberg` directory exists, that the commit SHA value in `gutenberg/.gutenberg-hash` matches `gutenberg.sha` in the `package.json` file, and it downloads a fresh copy if not.

While this will result in the necessary files not being present locally after running `npm install`, `gutenberg:verify` is specified as the first task executed when the `build` and `build:dev` scripts are run. Running either build script has been a requirement to run WordPress locally for some time now, so this does not introduce a new required step. It simply delays when the built asset will be retrieved from the GitHub Container Registry when necessary.

`postinstall` scripts should also be avoided entirely due to their significantly insecure nature (see #64543).

Follow up to [61492], [61873], and [62021].

Props jorbin, johnbillion.
Fixes #64874. See #64393, #64543.
Built from https://develop.svn.wordpress.org/trunk@62321


git-svn-id: http://core.svn.wordpress.org/trunk@61601 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '7.1-alpha-62320';
+$wp_version = '7.1-alpha-62321';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.