fix: align upload button layout in login background image section

web/templates/admin_settings.html

@@ -33,11 +33,11 @@
               <input type="file" name="login_bg" class="form-control" accept="image/png,image/jpeg,image/webp">
               <small class="form-hint">Max 5 MB. JPEG, PNG or WebP. The image is centered and fills the screen without distortion.</small>
             </div>
-            <div class="col-auto mb-3 d-flex align-items-end">
-              <button type="submit" class="btn btn-primary">
-                <i class="ti ti-upload"></i> Upload
-              </button>
-            </div>
+          </div>
+          <div class="form-footer">
+            <button type="submit" class="btn btn-primary">
+              <i class="ti ti-upload"></i> Upload
+            </button>
           </div>
         </form>
       </div>