Add support for method podcast.searchPodcast (#1572)

## List of changes
- added support for method podcast.searchPodcast from list of methods in
issue: #1222
- old podcast methods marked as *Deprecated* ( **Warning**: vk support
team said, that api for podcast is offline )
- added new model *VkNet/Model/Results/Podcasts/PodcastSearchInfo.cs*
and rebuilded model
*VkNet/Model/Results/Podcasts/PodcastsSearchResult.cs* for support new
format of answer from api method
- rebuilded test sources and test cases for 'podcast.searchPodcast'
method

[Source for
podcast.searchPodcast](https://dev.vk.com/ru/method/podcasts.searchPodcast)

## Additional info about podcast methods

![изображение](https://github.com/vknet/vk/assets/9554636/89360618-30ea-4d91-99f7-abdf50056d29)

---------

Co-authored-by: inyutin-maxim <[email protected]>

VkNet.Tests/Categories/Podcasts/SearchPodcastTest.cs

@@ -0,0 +1,80 @@
+using FluentAssertions;
+using VkNet.Tests.Infrastructure;
+using Xunit;
+
+namespace VkNet.Tests.Categories.Podcasts;
+
+public class SearchPodcastTest : CategoryBaseTest
+{
+	protected override string Folder => "Podcasts";
+
+	[Fact]
+	public void SearchPodcast()
+	{
+		Url = "https://api.vk.com/method/podcasts.searchPodcast";
+
+		ReadCategoryJsonPath(nameof(Api.Podcasts.SearchPodcast));
+
+		var result = Api.Podcasts.SearchPodcast(new()
+		{
+			SearchString = "наука",
+			Offset = 0,
+			Count = 100
+		});
+
+		result.Should().
+			NotBeNull();
+
+		result.ResultsTotal.
+			Should().
+			Be(32);
+
+		result.Podcasts[0].
+			OwnerUrl.
+			Should().
+			Be("https://vk.com/science_in_palm");
+
+		result.Podcasts[0].
+			Title.
+			Should().
+			Be("Наука в Ладошке");
+
+		result.Podcasts[0].
+			Covers.
+			Sizes[0].
+			Width.
+			Should().
+			Be(640);
+
+		result.Podcasts[0].
+			Covers.
+			Sizes[0].
+			Type.
+			Should().
+			Be("a");
+
+		result.Podcasts[4].
+			Title.
+			Should().
+			Be("Noosphere Studio | Наука");
+
+		result.Podcasts[4].
+			OwnerUrl.
+			Should()
+			.Be("https://vk.com/noosphere_studio");
+
+		result.Podcasts[4].
+			Covers.
+			Sizes[1].
+			Type.
+			Should()
+			.Be("c");
+
+		result.Podcasts[4].
+			Covers.
+			Sizes[2].
+			Height.
+			Should().
+			Be(160);
+	}
+}