fix: ensure token usage recording, validate response model on stream

lib/crewai/tests/cassettes/test_gpt_4_1[gpt-4.1-mini-2025-04-14].yaml

@@ -1,7 +1,6 @@
 interactions:
 - request:
-    body: '{"messages": [{"role": "user", "content": "What is the capital of France?"}],
-      "model": "gpt-4.1-mini-2025-04-14", "stop": []}'
+    body: '{"messages": [{"role": "user", "content": "What is the capital of France?"}], "model": "gpt-4.1-mini-2025-04-14", "stop": []}'
     headers:
       accept:
       - application/json
@@ -41,22 +40,12 @@ interactions:
     uri: https://api.openai.com/v1/chat/completions
   response:
     body:
-      string: !!binary |
-        H4sIAAAAAAAAAwAAAP//jJJPb9swDMXv/hSCznEQe+7S5LgAGzDs0P3paSgMRqJtZrIkSPTQoch3
-        H2Snsbt1wC4+8MdHv0fxKRNCkpZ7IVUHrHpv8nd3t4eIH77w4ePX+/b+8XP56bTdHE7dgb2Sq6Rw
-        xxMqflatleu9QSZnJ6wCAmOaWmyrmzflrqrejqB3Gk2StZ7zal3kPVnKy015k2+qvKgu8s6Rwij3
-        4nsmhBBP4zcZtRof5V5sVs+VHmOEFuX+2iSEDM6kioQYKTJYlqsZKmcZ7ej9W4dCgScGI1wj3gew
-        CgVFcQeB4nqpCtgMEZJ1OxizAGCtY0jRR78PF3K+OjSu9cEd4x9S2ZCl2NUBITqb3ER2Xo70nAnx
-        MG5ieBFO+uB6zzW7Hzj+rqimcXJ+gBneXhg7BjOXy3L1yrBaIwOZuFikVKA61LNy3joMmtwCZIvI
-        f3t5bfYUm2z7P+NnoBR6Rl37gJrUy7xzW8B0nf9qu654NCwjhp+ksGbCkJ5BYwODmU5Gxl+Rsa8b
-        si0GH2i6m8bX291xuztiVTQyO2e/AQAA//8DAP7WRo9GAwAA
+      string: "{\n  \"id\": \"chatcmpl-BP8CseGRtCJSUgUxQ2Lj70CjhCtpc\",\n  \"object\": \"chat.completion\",\n  \"created\": 1745329446,\n  \"model\": \"gpt-4.1-mini-2025-04-14\",\n  \"choices\": [\n    {\n      \"index\": 0,\n      \"message\": {\n        \"role\": \"assistant\",\n        \"content\": \"The capital of France is Paris.\",\n        \"refusal\": null,\n        \"annotations\": []\n      },\n      \"logprobs\": null,\n      \"finish_reason\": \"stop\"\n    }\n  ],\n  \"usage\": {\n    \"prompt_tokens\": 14,\n    \"completion_tokens\": 8,\n    \"total_tokens\": 22,\n    \"prompt_tokens_details\": {\n      \"cached_tokens\": 0,\n      \"audio_tokens\": 0\n    },\n    \"completion_tokens_details\": {\n      \"reasoning_tokens\": 0,\n      \"audio_tokens\": 0,\n      \"accepted_prediction_tokens\": 0,\n      \"rejected_prediction_tokens\": 0\n    }\n  },\n  \"service_tier\": \"default\",\n  \"system_fingerprint\": \"fp_79b79be41f\"\n}\n"
     headers:
       CF-RAY:
       - 93458dcf6d0ef53b-GRU
       Connection:
       - keep-alive
-      Content-Encoding:
-      - gzip
       Content-Type:
       - application/json
       Date: