fix: Resolve CA1056 code analysis violations in web search connectors

- Changed Url property from string? to Uri? in TavilyWebPage
- Changed Url property from string? to Uri? in BraveWebPage
- Updated constructors to accept Uri? parameters
- Added null-safe string-to-Uri conversions in factory methods
- Fixed image URL handling in TavilyTextSearch

Resolves all 31 CA1056 violations (URI properties should not be strings).

Author: alzarei

dotnet/src/Plugins/Plugins.Web/Brave/BraveWebPage.cs

@@ -18,7 +18,7 @@ public sealed class BraveWebPage
     /// <summary>
     /// Gets or sets the URL of the web page.
     /// </summary>
-    public string? Url { get; set; }
+    public Uri? Url { get; set; }
 
     /// <summary>
     /// Gets or sets the description of the web page.
@@ -118,7 +118,7 @@ public BraveWebPage()
     /// <param name="url">The URL of the web page.</param>
     /// <param name="description">The description of the web page.</param>
     /// <param name="type">The type of the search result.</param>
-    public BraveWebPage(string? title, string? url, string? description, string? type = null)
+    public BraveWebPage(string? title, Uri? url, string? description, string? type = null)
     {
         this.Title = title;
         this.Url = url;
@@ -133,7 +133,8 @@ public BraveWebPage(string? title, string? url, string? description, string? typ
     /// <returns>A new BraveWebPage instance.</returns>
     internal static BraveWebPage FromWebResult(BraveWebResult result)
     {
-        return new BraveWebPage(result.Title, result.Url, result.Description, result.Type)
+        Uri? url = string.IsNullOrWhiteSpace(result.Url) ? null : new Uri(result.Url);
+        return new BraveWebPage(result.Title, url, result.Description, result.Type)
         {
             Age = result.Age,
             PageAge = result.PageAge,

dotnet/src/Plugins/Plugins.Web/Tavily/TavilyTextSearch.cs

@@ -569,10 +569,11 @@ private async IAsyncEnumerable<object> GetResultsAsWebPageAsync(TavilySearchResp
         {
             foreach (var image in searchResponse.Images!)
             {
-                // For images, create a basic TavilyWebPage representation
+                //For images, create a basic TavilyWebPage representation
+                Uri? imageUri = string.IsNullOrWhiteSpace(image.Url) ? null : new Uri(image.Url);
                 yield return new TavilyWebPage(
                     title: "Image Result",
-                    url: image.Url,
+                    url: imageUri,
                     content: image.Description ?? string.Empty,
                     score: 0.0
                 );

dotnet/src/Plugins/Plugins.Web/Tavily/TavilyWebPage.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+using System;
+
 namespace Microsoft.SemanticKernel.Plugins.Web.Tavily;
 
 /// <summary>
@@ -16,7 +18,7 @@ public sealed class TavilyWebPage
     /// <summary>
     /// Gets or sets the URL of the web page.
     /// </summary>
-    public string? Url { get; set; }
+    public Uri? Url { get; set; }
 
     /// <summary>
     /// Gets or sets the content/description of the web page.
@@ -78,7 +80,7 @@ public TavilyWebPage()
     /// <param name="content">The content/description of the web page.</param>
     /// <param name="score">The relevance score.</param>
     /// <param name="rawContent">The raw content (optional).</param>
-    public TavilyWebPage(string? title, string? url, string? content, double score, string? rawContent = null)
+    public TavilyWebPage(string? title, Uri? url, string? content, double score, string? rawContent = null)
     {
         this.Title = title;
         this.Url = url;
@@ -94,6 +96,7 @@ public TavilyWebPage(string? title, string? url, string? content, double score,
     /// <returns>A new TavilyWebPage instance.</returns>
     internal static TavilyWebPage FromSearchResult(TavilySearchResult result)
     {
-        return new TavilyWebPage(result.Title, result.Url, result.Content, result.Score, result.RawContent);
+        Uri? url = string.IsNullOrWhiteSpace(result.Url) ? null : new Uri(result.Url);
+        return new TavilyWebPage(result.Title, url, result.Content, result.Score, result.RawContent);
     }
 }