[C#] chore: make assistants planner experimental (#910)

## Linked issues

closes: #905 

## Details

Change assistant planner related class' namespace from
`Microsoft.Teams.AI.AI.Planners` to
`Microsoft.Teams.AI.AI.Planners.Experimental`

## Attestation Checklist

- [x] My code follows the style guidelines of this project

- I have checked for/fixed spelling, linting, and other errors
- I have commented my code for clarity
- I have made corresponding changes to the documentation (we use
[TypeDoc](https://typedoc.org/) to document our code)
- My changes generate no new warnings
- I have added tests that validates my changes, and provides sufficient
test coverage. I have tested with:
  - Local testing
  - E2E testing in Teams
- New and existing unit tests pass locally with my changes

Author: singhk97

dotnet/packages/Microsoft.TeamsAI/Microsoft.TeamsAI.Tests/AITests/AssistantsPlannerTests.cs

@@ -1,12 +1,13 @@
 using Microsoft.Bot.Builder;
 using Microsoft.Bot.Schema;
 using Microsoft.Teams.AI.AI;
-using Microsoft.Teams.AI.AI.Planners;
+using Microsoft.Teams.AI.AI.Planners.Experimental;
 using Microsoft.Teams.AI.Exceptions;
 using Record = Microsoft.Teams.AI.State.Record;
 using Microsoft.Teams.AI.Tests.TestUtils;
 using Moq;
 using System.Reflection;
+using Microsoft.Teams.AI.AI.Planners;
 
 namespace Microsoft.Teams.AI.Tests.AITests
 {

dotnet/packages/Microsoft.TeamsAI/Microsoft.TeamsAI/AI/Planners/AssistantsPlanner.cs

@@ -7,7 +7,10 @@
 using Microsoft.Teams.AI.Utilities;
 using System.Text.Json;
 
-namespace Microsoft.Teams.AI.AI.Planners
+// Assistants API is currently in beta and is subject to change.
+#pragma warning disable IDE0130 // Namespace does not match folder structure
+namespace Microsoft.Teams.AI.AI.Planners.Experimental
+#pragma warning restore IDE0130 // Namespace does not match folder structure
 {
     /// <summary>
     /// A planner that uses OpenAI's Assistants APIs to generate plans.

dotnet/packages/Microsoft.TeamsAI/Microsoft.TeamsAI/AI/Planners/AssistantsPlannerOptions.cs

@@ -1,6 +1,9 @@
 using Microsoft.Teams.AI.Utilities;
 
-namespace Microsoft.Teams.AI.AI.Planners
+// Assistants API is currently in beta and is subject to change.
+#pragma warning disable IDE0130 // Namespace does not match folder structure
+namespace Microsoft.Teams.AI.AI.Planners.Experimental
+#pragma warning restore IDE0130 // Namespace does not match folder structure
 {
     /// <summary>
     /// Options for the Assistants planner.

dotnet/packages/Microsoft.TeamsAI/Microsoft.TeamsAI/AI/Planners/AssistantsState.cs

@@ -1,6 +1,9 @@
 using Microsoft.Teams.AI.State;
 
-namespace Microsoft.Teams.AI.AI.Planners
+// Assistants API is currently in beta and is subject to change.
+#pragma warning disable IDE0130 // Namespace does not match folder structure
+namespace Microsoft.Teams.AI.AI.Planners.Experimental
+#pragma warning restore IDE0130 // Namespace does not match folder structure
 {
     /// <summary>
     /// Model represents assistants state.

dotnet/samples/06.assistants.a.mathBot/ActivityHandlers.cs

@@ -1,6 +1,6 @@
 using Microsoft.Bot.Builder;
 using Microsoft.Teams.AI;
-using Microsoft.Teams.AI.AI.Planners;
+using Microsoft.Teams.AI.AI.Planners.Experimental;
 
 namespace MathBot
 {

dotnet/samples/06.assistants.a.mathBot/Program.cs

@@ -4,7 +4,9 @@
 using Microsoft.Teams.AI;
 using Microsoft.Teams.AI.AI;
 using Microsoft.Teams.AI.AI.OpenAI.Models;
+using Microsoft.Teams.AI.AI.Planners.Experimental;
 using Microsoft.Teams.AI.AI.Planners;
+
 using MathBot;
 
 var builder = WebApplication.CreateBuilder(args);

dotnet/samples/06.assistants.b.orderBot/ActivityHandlers.cs

@@ -1,6 +1,6 @@
 using Microsoft.Bot.Builder;
 using Microsoft.Teams.AI;
-using Microsoft.Teams.AI.AI.Planners;
+using Microsoft.Teams.AI.AI.Planners.Experimental;
 
 namespace OrderBot
 {

dotnet/samples/06.assistants.b.orderBot/Program.cs

@@ -4,6 +4,7 @@
 using Microsoft.Teams.AI;
 using Microsoft.Teams.AI.AI;
 using Microsoft.Teams.AI.AI.OpenAI.Models;
+using Microsoft.Teams.AI.AI.Planners.Experimental;
 using Microsoft.Teams.AI.AI.Planners;
 using OrderBot;
 using OrderBot.Models;