Use string serializtion/deserialization for DateTime structure

src/ReportPortal.Client/Abstractions/Requests/CreateLogItemRequest.cs

@@ -24,7 +24,6 @@ public class CreateLogItemRequest
         /// <summary>
         /// Date time of log item.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime Time { get; set; } = DateTime.UtcNow;
 
         /// <summary>

src/ReportPortal.Client/Abstractions/Requests/FinishLaunchRequest.cs

@@ -1,6 +1,4 @@
-using ReportPortal.Client.Converters;
-using System;
-using System.Text.Json.Serialization;
+using System;
 
 namespace ReportPortal.Client.Abstractions.Requests
 {
@@ -12,7 +10,6 @@ public class FinishLaunchRequest
         /// <summary>
         /// Gets or sets the date and time when the launch execution is finished.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime EndTime { get; set; } = DateTime.UtcNow;
     }
 }

src/ReportPortal.Client/Abstractions/Requests/FinishTestItemRequest.cs

@@ -20,7 +20,6 @@ public class FinishTestItemRequest
         /// <summary>
         /// Gets or sets the date and time when the test item is finished.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime EndTime { get; set; } = DateTime.UtcNow;
 
         /// <summary>

src/ReportPortal.Client/Abstractions/Requests/MergeLaunchesRequest.cs

@@ -30,13 +30,11 @@ public class MergeLaunchesRequest
         /// <summary>
         /// Gets or sets the date and time when the launch is executed.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime StartTime { get; set; }
 
         /// <summary>
         /// Gets or sets the date and time when the launch is finished.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime EndTime { get; set; }
 
         /// <summary>

src/ReportPortal.Client/Abstractions/Requests/StartLaunchRequest.cs

@@ -30,7 +30,6 @@ public class StartLaunchRequest
         /// <summary>
         /// Gets or sets the date and time when the launch is executed.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime StartTime { get; set; } = DateTime.UtcNow;
 
         /// <summary>

src/ReportPortal.Client/Abstractions/Requests/StartTestItemRequest.cs

@@ -29,7 +29,6 @@ public class StartTestItemRequest
         /// <summary>
         /// Date time when new test item is created.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime StartTime { get; set; } = DateTime.UtcNow;
 
         /// <summary>

src/ReportPortal.Client/Abstractions/Responses/LaunchResponse.cs

@@ -45,13 +45,11 @@ public class LaunchResponse
         /// <summary>
         /// Gets or sets the start time of the launch.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime StartTime { get; set; }
 
         /// <summary>
         /// Gets or sets the end time of the launch.
         /// </summary>
-        [JsonConverter(typeof(NullableDateTimeUnixEpochConverter))]
         public DateTime? EndTime { get; set; }
 
         /// <summary>

src/ReportPortal.Client/Abstractions/Responses/LogItemResponse.cs

@@ -34,7 +34,6 @@ public class LogItemResponse
         /// <summary>
         /// Gets or sets the time when the log item was created.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime Time { get; set; }
 
         /// <summary>

src/ReportPortal.Client/Abstractions/Responses/TestItemResponse.cs

@@ -40,13 +40,11 @@ public class TestItemResponse
         /// <summary>
         /// Gets or sets the start time of the test item.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime StartTime { get; set; }
 
         /// <summary>
         /// Gets or sets the end time of the test item.
         /// </summary>
-        [JsonConverter(typeof(NullableDateTimeUnixEpochConverter))]
         public DateTime? EndTime { get; set; }
 
         /// <summary>
@@ -191,7 +189,6 @@ public class ExternalSystemIssue
         /// <summary>
         /// Gets or sets the submit date of the external system issue.
         /// </summary>
-        [JsonConverter(typeof(DateTimeUnixEpochConverter))]
         public DateTime SubmitDate { get; set; }
 
         /// <summary>