Encryption: Cache new DEKs (only) after a caution period (#60664)

* Encryption: Cache new DEKs (only) after commit

* Fix typo

* Update secrets manager tests with new failing case

* Update secrets manager tests with new clarifications (comments)

* Correct broken method calls

* Unify methods

* Cache data keys only after a caution period

* Caution period for data keys caching only for encrypt ops

pkg/services/secrets/fakes/fake_store.go

@@ -4,7 +4,6 @@ import (
 	"context"
 
 	"github.com/grafana/grafana/pkg/services/secrets"
-	"xorm.io/xorm"
 )
 
 type FakeSecretsStore struct {
@@ -47,11 +46,6 @@ func (f FakeSecretsStore) CreateDataKey(_ context.Context, dataKey *secrets.Data
 	return nil
 }
 
-func (f FakeSecretsStore) CreateDataKeyWithDBSession(_ context.Context, dataKey *secrets.DataKey, _ *xorm.Session) error {
-	f.store[dataKey.Id] = dataKey
-	return nil
-}
-
 func (f FakeSecretsStore) DisableDataKeys(_ context.Context) error {
 	for id := range f.store {
 		f.store[id].Active = false