DRA: treat AdminAccess as a new feature gated field

Using the "normal" logic for a feature gated field simplifies the
implementation of the feature gate.

There is one (entirely theoretic!) problem with updating from 1.31: if a claim
was allocated in 1.31 with admin access, the status field was not set because
it didn't exist yet. If a driver now follows the current definition of "unset =
off", then it will not grant admin access even though it should. This is
theoretic because drivers are starting to support admin access with 1.32, so
there shouldn't be any claim where this problem could occur.

Kubernetes-commit: 4419568259590c35f1dab69aabec3d740944a51d

applyconfigurations/internal/internal.go

@@ -12419,7 +12419,6 @@ var schemaYAML = typed.YAMLObject(`types:
     - name: adminAccess
       type:
         scalar: boolean
-      default: false
     - name: allocationMode
       type:
         scalar: string