Add/Update Action Context variables to main Context for Stepwise Planner

[akshaykokane]

Add ActionContext variable to main Context

Motivation and Context

Please help reviewers and future users, providing the following information:

1. Why is this change required?
   In stepwise planner, for every action we create new Action Context. Each action can result into adding new context variables. These context variables are potentially used for executing of next action. Currently, the context variables created from Action are ignored and only the "Result" is added back to context. So the action only adds Result to SKContext and doesn't update the context variables in Kernel context.

2. What problem does it solve?

• Chaining of multiple skills using Stepwise Planner and Context Variables (inline with SequentialPlanner)
• Before implementing Action, reads from main context to check if variable is available if not try to get it from {actionVariables}

3. What scenario does it contribute to?
   Stepwise Planner uses Context Variables from previous actions to invoke next action

4. If it fixes an open issue, please link to the issue here. Stepwise Planner doesn't updates Context Variables from actions #1894

Description

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows SK Contribution Guidelines (https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
• The code follows the .NET coding conventions (https://learn.microsoft.com/dotnet/csharp/fundamentals/coding-style/coding-conventions) verified with dotnet format
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[shawncal]

@akshaykokane Thanks for the contribution! Looking through this, even after a rebase, I see some use of classes that no longer exist (i.e TrustAwareString) which only means it look us too long to get to this PR. I'm going to close it, only because it's clear that the solution is no longer applicable. That said, the Issue #1894 remains open -- if you can confirm the issue is still... an issue, feel free to re-open the PR with an updated solution, and add me (@shawncal and Roger @RogerBarreto) as reviewers.

Thanks! And apologies for the delay in reviewing this. Your contributions are appreciated, and we'd love to see more!