Enable .NET functions in check-pr for Agent-specific functions (#2119)

Enable the .NET functions for the agent by sending the agent the URI for the `-net` service.

Also fix some things causing failures when using the .NET functions (`CouldShrinkScaleset` was not implemented).

Improve error handling around table serialization/deserialization, fix an issue with int64/long mismatch between Python & C# code.

----

For `check-pr` testing:

1. There's a new parameter `enable_dotnet` which maps directly to the `--enable_dotnet` switch on `deploy.py`.
2. If you put `agent` there, all the `agent_*` functions will be enabled for .NET and disabled for Python.
3. If `agent_can_schedule` is disabled on the Python side, it will automatically tell the agent to use the .NET functions.

So to test the .NET agent functions, do a `check-pr` run with `enable_dotnet` set to `agent` and it should all work.

src/deployment/deploy.py

@@ -4,6 +4,7 @@
 # Licensed under the MIT License.
 
 import argparse
+import itertools
 import json
 import logging
 import os
@@ -1094,9 +1095,26 @@ class Client:
 
     def enable_dotnet_func(self) -> None:
         if self.enable_dotnet:
+
+            def expand_agent(f: str) -> List[str]:
+                # 'agent' is permitted as a shortcut for the agent functions
+                if f == "agent":
+                    return [
+                        "agent_can_schedule",
+                        "agent_commands",
+                        "agent_events",
+                        "agent_registration",
+                    ]
+                else:
+                    return [f]
+
+            enable_dotnet = itertools.chain.from_iterable(
+                map(expand_agent, self.enable_dotnet)
+            )
+
             func = shutil.which("az")
             assert func is not None
-            for function_name in self.enable_dotnet:
+            for function_name in enable_dotnet:
                 format_name = function_name.split("_")
                 dotnet_name = "".join(x.title() for x in format_name)
                 error: Optional[subprocess.CalledProcessError] = None