Omitting chef last run checks for OD

Summary:
Reason:
Chef does not run on ODs because these machines can be reserved for only 18 hours, and sudo access is not permitted on ODs.
More details in this WP post -
https://fb.workplace.com/groups/vscode.feedback/permalink/9190771900989273/

Background:
Our goal is to ensure that Chef is functioning correctly on the user's machine to confirm they have the latest version of Eden installed. Currently, this check is not limited to any specific platform. In this case, it seems that the health report cannot access the Chef log path to accurately read the last updated timestamp, leading to an exception block being triggered. This check was introduced in the following diff: D66439133.

Reviewed By: genevievehelsel

Differential Revision: D68587542

fbshipit-source-id: 0e8b6288ca0cddc9315d5e6ce61df34ec99f4798

eden/fs/cli/main.py

@@ -50,6 +50,13 @@ def set_sample_rate(self, automation: int) -> None:
     # pyre-fixme[31]: Expression `eden.fs.cli.main.ParTelemetryStub()` is not a
     #  valid type.
     usage = ParTelemetryStub()
+try:
+    from eden.fs.cli.facebook.hostcaps import is_on_demand
+except ImportError:
+    # in OSS define a stub
+    def is_on_demand() -> bool:
+        return False
+
 
 from eden.fs.cli.buck import get_buck_command, run_buck_command
 from eden.fs.cli.config import HG_REPO_TYPES
@@ -1320,12 +1327,14 @@ def is_repo_mounted(self, instance: EdenInstance, mounts: List[str]) -> bool:
 
     def is_chef_running(self) -> bool:
         """Examine the status of Chef runs."""
-        chef_log_path = get_chef_log_path(platform.system())
-        if chef_log_path is None or chef_log_path == "":
-            print(f"Skipping chef run check for platform {platform.system()}.")
+        if is_on_demand() or get_chef_log_path(platform.system()) is None:
+            print("Skipping chef run check for unsupported platform.")
             return True
+
+        chef_log_path = get_chef_log_path(platform.system())
+
         try:
-            with open(chef_log_path, "r") as f:
+            with open(str(chef_log_path), "r") as f:
                 chef_log_raw = f.read()
                 chef_log = json.loads(chef_log_raw)
                 last_chef_run_sec = chef_log[CHEF_LOG_TIMESTAMP_KEY]