chore: remove GetDAO from Permissions interface

THis was discussed at some point but it turns out is not going to be
used by Boards2.

examples/gno.land/r/nt/boards2/v1/permissions.gno

@@ -1,10 +1,6 @@
 package boards2
 
-import (
-	"std"
-
-	"gno.land/p/nt/commondao"
-)
+import "std"
 
 const (
 	PermissionBoardCreate         Permission = "board:create"
@@ -64,9 +60,5 @@ type (
 
 		// HasUser checks if a user exists.
 		HasUser(std.Address) bool
-
-		// GetDAO returns the underlying DAO.
-		// Returned value can be nil if the implementation doesn't have a DAO.
-		GetDAO() *commondao.CommonDAO // TODO: should return an interface
 	}
 )

examples/gno.land/r/nt/boards2/v1/permissions_default.gno

@@ -127,12 +127,6 @@ func (dp DefaultPermissions) HasUser(user std.Address) bool {
 	return dp.users.Has(user.String())
 }
 
-// GetDAO returns the underlying DAO.
-// Returned value can be nil if the implementation doesn't have a DAO.
-func (dp DefaultPermissions) GetDAO() *commondao.CommonDAO {
-	return dp.dao
-}
-
 // WithPermission calls a callback when a user has a specific permission.
 // It panics on error or when a handler panics.
 // Callbacks are by default called when there is no handle registered for the permission.