Improve license switching process to make it more user-friendly

[joejoe04]

Is your feature request related to a problem? Please describe.
WP Rocket settings are reset to default when a license is switched by placing the following in wp-config.php:

define( 'WP_ROCKET_EMAIL', 'EMAIL');
define( 'WP_ROCKET_KEY', 'APIKEY');

This may not be the best experience for users for at least a couple of reasons:

• They may not be aware this will happen and could lose complex configurations (exclusions, etc)
• Sometimes agencies create sites using their Infinite license and then switch to user's license when site is complete and it's not the smoothest process for them to need to export settings and then import them after the switch.
• Support sometimes recommends resetting the API key to revalidate the license. This is an important one related to 'stolen plugin' cases. Users may need to reset their API key for potentially hundreds of sites, and this proposed change would prevent users from needing to export options and re-import after changing the license for them all.

Describe the solution you'd like
There are some settings that contain confidential information (Cloudflare API key, etc), and those should go back to default, but general settings like optimizations being enabled or not, exclusions, and safelists could be maintained as they were before during/after the license switch.

Additional context
https://secure.helpscout.net/conversation/2586391894/489528/
https://wp-media.slack.com/archives/C08N8J6VC/p1714675850685209