Reduce transient cache time

[stevegrunwell]

When a site first reaches out to the WP101 Plugin SaaS to authenticate, the SaaS assigns it a public API key and its capabilities, which is then cached in a non-expiring transient.

If a subscriber were to change plans or otherwise impact the capabilities available to them, they would need to explicitly delete this transient, which is an unnecessary step.

Instead of caching for an unlimited amount of time, this should be lowered to something more reasonable (an hour or less), ideally 15min or so.