[shotwell] Tumblr: Do not accidentally invalidate credentials

[Jens Georg <jensgeorg src gnome org>]

commit 8cfc86caead9633932a54d97a9c25bd853233e18
Author: Jens Georg <mail jensge org>
Date:   Wed Sep 7 22:18:07 2022 +0200

    Tumblr: Do not accidentally invalidate credentials
    
    Even if we do not use the Username with Tumblr, the class needs it. On
    successful authentication we store "unused". When authenticating with
    those credentials later, the username is set to "" causing the username
    "secret" to be removed, rendering all of the stored credentials invalid
    
    Fixed #4993

 plugins/authenticator/shotwell/TumblrAuthenticator.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/plugins/authenticator/shotwell/TumblrAuthenticator.vala 
b/plugins/authenticator/shotwell/TumblrAuthenticator.vala
index 7d128b0a..385572cf 100644
--- a/plugins/authenticator/shotwell/TumblrAuthenticator.vala
+++ b/plugins/authenticator/shotwell/TumblrAuthenticator.vala
@@ -135,7 +135,7 @@ namespace Publishing.Authenticator.Shotwell.Tumblr {
                 debug("attempt start: a persistent session is available; using it");
 
                 session.authenticate_from_persistent_credentials(get_persistent_access_phase_token(),
-                        get_persistent_access_phase_token_secret(), "");
+                        get_persistent_access_phase_token_secret(), "unused");
             } else {
                 debug("attempt start: no persistent session available; showing login welcome pane");