Python: Improve handling the Dapr process context

[moonbox3]

Motivation and Context

There is a bug in the current Dapr runtime code that prohibits trying to get the Dapr process context out from a process once it's finished. This is related to incorrect handling of serializing/deserializing the Dapr process context. Additionally, in a state that handles KernelProcessStepState, due to Dapr serialization constraints, the step step injected to a step is not the actual object. We use Pydantic's model_validate to get the actual step object, but and we need to make sure we re-assign that object back to the underlying step state so the objects don't diverge (model_validate creates a new object).

Description

Improve the handling for the Dapr process context so we're properly serializing data through the Dapr process.

• Fixes the issue brought up in the discussion: Adding AgentGroupChat to the kernel for future use in Process Framework #10234

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
semantic_kernel/processes/dapr_runtime
dapr_kernel_process_context.py	35	2	94%	25, 27
dapr_step_info.py	32	2	94%	31, 40
semantic_kernel/processes/dapr_runtime/actors
process_actor.py	245	114	53%	72–76, 81, 84, 90, 93, 97, 102, 105, 121–124, 129, 142, 160–164, 169, 179, 184, 193–204, 208–210, 218–234, 239, 255–316, 321, 332, 346–354, 357–364, 368–396, 427–440
step_actor.py	263	133	49%	81–85, 90, 93, 97–98, 110–112, 156–159, 173–175, 183, 187–188, 214, 222–223, 239–246, 253–254, 262–360, 364, 368–371, 375–391, 395–419, 423–441, 445–448, 452, 456–459
semantic_kernel/processes/local_runtime
local_process.py	138	53	62%	66, 103, 113, 131–142, 176–203, 207–212, 216, 220–226, 230–241, 245–246
TOTAL	19594	2554	87%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3207	5 💤	0 ❌	0 🔥	1m 32s ⏱️