Add missing actions and tests for lockPostAutosaving, unlockPostAutosaving

[adamsilverstein]

Description

Add missing actions for #16249

The original PR was missing the actions for the post autosave lock. These are inbtroduced here along with tests.

How has this been tested?

• Create a new post
• Make changes and note autosave firing
• Lock autosaving: in the console, type wp.data.dispatch( 'core/editor' ).lockPostAutosaving( 'mylock' );
• Make changes, note autosaving does not occur. Regular updates work as expected (clicking the update button)
• Unlock autosaving: in the console, type wp.data.dispatch( 'core/editor' ).unlockPostAutosaving( 'mylock' );

Types of changes

• Add actions for lockPostAutosaving and unlockPostAutosaving with matching tests.

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR. .

[desaiuditd]

Looks good 👍🏼