fix: some telemetry APIs don't currently work (#1188)

Summary:

This bug is surfaced by using the http LS client. The issue is that
non-scalar values in 'GET' method are `body` params in fastAPI, but our
spec generation script doesn't respect that. We fix by just making them
POST method instead.

Test Plan:
Test API call with newly sync'd client
(https://github.com/meta-llama/llama-stack-client-python/pull/149)

<img width="1114" alt="image"
src="https://github.com/user-attachments/assets/7710aca5-d163-4e00-a465-14e6fcaac2b2"
/>

llama_stack/distribution/server/server.py

@@ -481,6 +481,8 @@ def main():
 def extract_path_params(route: str) -> List[str]:
     segments = route.split("/")
     params = [seg[1:-1] for seg in segments if seg.startswith("{") and seg.endswith("}")]
+    # to handle path params like {param:path}
+    params = [param.split(":")[0] for param in params]
     return params