fix: consistent permission check on user v2 (#8807)

# Which Problems Are Solved

Some user v2 API calls checked for permission only on the user itself.

# How the Problems Are Solved

Consistent check for permissions on user v2 API.

# Additional Changes

None

# Additional Context

Closes #7944

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>

internal/command/user_v2.go

@@ -127,6 +127,16 @@ func (c *Commands) checkPermissionUpdateUser(ctx context.Context, resourceOwner,
 	return nil
 }
 
+func (c *Commands) checkPermissionUpdateUserCredentials(ctx context.Context, resourceOwner, userID string) error {
+	if userID != "" && userID == authz.GetCtxData(ctx).UserID {
+		return nil
+	}
+	if err := c.checkPermission(ctx, domain.PermissionUserCredentialWrite, resourceOwner, userID); err != nil {
+		return err
+	}
+	return nil
+}
+
 func (c *Commands) checkPermissionDeleteUser(ctx context.Context, resourceOwner, userID string) error {
 	if userID != "" && userID == authz.GetCtxData(ctx).UserID {
 		return nil