Allow non-existent options to be monitored.

[bradyvercher]

Context

This fixes the monitoring of non-existent options. WordPress triggers a different filter when an option doesn't exist. The same filter is used again on lines 217 and 230.

Very cool plugin! I was about to build something very similar before I stumbled on this.

Summary

This PR can be summarized in the following changelog entry:

• Fix monitoring of non-existent options.

Relevant technical choices:

• str_starts_with() is a little easier to read, but is PHP 8+ if that's relevant.

Test instructions

Relevant test scenarios

• Changes should be tested with the browser console open
• Changes should be tested on different posts/pages/taxonomies/custom post types/custom taxonomies
• Changes should be tested on different editors (Block/Classic/Elementor/other)
• Changes should be tested on different browsers
• Changes should be tested on multisite

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Documentation

• I have written documentation for this change.

Quality assurance

• I have tested this code to the best of my abilities.
• I have added unit tests to verify the code works as intended.
• I have checked that the base branch is correctly set.

Fixes #

[jdevalk]

Thanks @bradyvercher !!