Combine vendor-init-actionable with vendor-init-readable

Historically, vendor-init-actionable was created since the various
property_contexts files were not yet available when init parses its
scripts.  Since then, the property_contexts files are now always
available when init parses its scripts, so we can collapse these two
categories.

Specifically, this change ensures that all of the properties in the
previous 'stable_properties.h' file in init, which contained the
vendor-init-actionable properties, are able to be read by init
according to SEPolicy.

Bug: 71814576
Test: vendor_init fails to use non-readable properties as a trigger
Test: vendor_init successfully uses readable properties as a trigger

Change-Id: Ic6d9919b6047f3076a1a19fc26295c6a77aca627