Update .NET SDK to support Conversation API Tool Calling

[bibryam]

Implement Conversation API Tool Calling support in .NET SDK (dapr/dapr#8816).

Acceptance Criteria

• SDK includes support for tool calling.
• SDK examples updated to reflect the new API capabilities.
• Quickstarts updated to use the new version of the SDK

[WhitWaldo]

Moving this into the .NET SDK repo

[WhitWaldo]

@bibryam Couple of thoughts:

• The .NET SDK doesn't really reflect a changed status of the APIs except from pre-release to stable, so I don't believe anything is necessary to support alpha to beta in this case.
• I've implemented the support for the streaming responses in this PR and will merge it after the upstream bits are similarly merged so the protos stay in sync.
• I don't see that there's any associated PR on dapr/dapr with the tool support issue you opened. Is that forthcoming?

[bibryam]

@WhitWaldo great to know you are on top of these!
I created the issue for any SDK work that needs to happen due to runtime changes from the above 3 issues. @filintod is working on them, but I couldn't assign him to the issues (maybe you can).
Tool calling a blocker for conversation api use in dapr-agents and we need to get that in. Response streaming and promotion to beta are less critical.
I see a minor change for .net in the conversation api http quickstart, change from v1.0-alpha1 to beta, that might be all.

[WhitWaldo]

I'm unable to make any progress on the tool calling aspect unless you can point me to the updated protos for that in whatever associated PR is available, if any.

I can only assign someone if they have contributed previously, and I do not see their name on the list. I would encourage you to ask them to comment "/assign" on the issue to achieve the same effect.

Streaming responses had a commented proto available, so that work is completed pending its merge into Dapr/Dapr. I'll tweak the example and documentation accordingly as well.

[filintod]

@WhitWaldo the protos are in this PR dapr/dapr#8829, but there is no review on them yet