Explicitly globalize $wp_local_package

[danielbachhuber]

It's included in version.php for non-US English locales.

Discovered in ​https://github.com/wp-cli/wp-cli/pull/2287

[danielbachhuber]

We have some instances of isset( $wp_local_package ) in the codebase, but the check performs as expected:

salty-wordpress ➜  wordpress-test.dev  wp shell
wp> global $wp_local_package;
wp> isset( $wp_local_package );
bool(false)

[ocean90]

In 36557:

Make $wp_local_package explicitly global in wp-settings.php.

Props danielbachhuber.
Fixes #34975.