Core Data: Add checks to actions and selectors to avoid throwing errors when the relevant config is not loaded.

[epiqueras]

Description

This PR adds some checks and guards to avoid throwing errors when editEntityRecord or isEditedPostDirty are called without the relevant entity config being loaded.

How has this been tested?

It was verified that running:

wp.data.dispatch( 'core' ).editEntityRecord( 'someKind', 'someName', 'someId', {} )

and

wp.data.select( 'core' ).getEntityRecordNonTransientEdits( 'someKind', 'someName', 'someId' )

for inexistent entity configs is handled gracefully.

Types of Changes

Bug Fix: editEntityRecord and isEditedPostDirty no longer throw an error when called before core-data is initialized.

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. .

[nerrad]

Looks good to me.

[youknowriad]

Do you think we can add some unit tests, to ensure these selectors/actions don't break when called early.

[epiqueras]

Updated and Tested! 🚀

[youknowriad]

Cool