web/flows: fix missing fallback for flow logo (#9487)

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

web/src/flow/FlowExecutor.ts

@@ -441,7 +441,10 @@ export class FlowExecutor extends Interface implements StageHost {
 
     renderChallengeWrapper(): TemplateResult {
         const logo = html`<div class="pf-c-login__main-header pf-c-brand ak-brand">
-            <img src="${first(this.brand?.brandingLogo, "")}" alt="authentik Logo" />
+            <img
+                src="${first(this.brand?.brandingLogo, globalAK()?.brand.brandingLogo, "")}"
+                alt="authentik Logo"
+            />
         </div>`;
         if (!this.challenge) {
             return html`${logo}<ak-empty-state ?loading=${true} header=${msg("Loading")}>