Preserve SplashscreenLocation when updating branding config (#13756)

* add BrandingOptionsDto and add branding endpoints

* refactor new HttpGet Configuration Branding into existing API calls

* Add BrandingOptions to _ignoredConfigurations for openAPI

* rename BrandOptionsDto to BrandingOptionsDto

MediaBrowser.Model/Branding/BrandingOptions.cs

@@ -1,5 +1,3 @@
-using System.Text.Json.Serialization;
-
 namespace MediaBrowser.Model.Branding;
 
 /// <summary>
@@ -27,10 +25,5 @@ public class BrandingOptions
     /// <summary>
     /// Gets or sets the splashscreen location on disk.
     /// </summary>
-    /// <remarks>
-    /// Not served via the API.
-    /// Only used to save the custom uploaded user splashscreen in the configuration file.
-    /// </remarks>
-    [JsonIgnore]
     public string? SplashscreenLocation { get; set; }
 }

MediaBrowser.Model/Branding/BrandingOptionsDto.cs

@@ -0,0 +1,25 @@
+namespace MediaBrowser.Model.Branding;
+
+/// <summary>
+/// The branding options DTO for API use.
+/// This DTO excludes SplashscreenLocation to prevent it from being updated via API.
+/// </summary>
+public class BrandingOptionsDto
+{
+    /// <summary>
+    /// Gets or sets the login disclaimer.
+    /// </summary>
+    /// <value>The login disclaimer.</value>
+    public string? LoginDisclaimer { get; set; }
+
+    /// <summary>
+    /// Gets or sets the custom CSS.
+    /// </summary>
+    /// <value>The custom CSS.</value>
+    public string? CustomCss { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to enable the splashscreen.
+    /// </summary>
+    public bool SplashscreenEnabled { get; set; } = false;
+}