fix: update tests to use new mcp_authorization field

Updates integration tests to use the new mcp_authorization field
instead of the old method of passing Authorization in mcp_headers.

Changes:
- tests/integration/tool_runtime/test_mcp.py
- tests/integration/inference/test_tools_with_schemas.py
- tests/integration/tool_runtime/test_mcp_json_schema.py (6 occurrences)

All tests now use:
  provider_data = {"mcp_authorization": {uri: AUTH_TOKEN}}

Instead of the old rejected format:
  provider_data = {"mcp_headers": {uri: {"Authorization": f"Bearer {AUTH_TOKEN}"}}}

This aligns with the security architecture that prevents
accidentally leaking inference tokens to MCP servers.

tests/integration/tool_runtime/test_mcp.py

@@ -43,10 +43,8 @@ def test_mcp_invocation(llama_stack_client, text_model_id, mcp_server):
     )
 
     provider_data = {
-        "mcp_headers": {
-            uri: {
-                "Authorization": f"Bearer {AUTH_TOKEN}",
-            },
+        "mcp_authorization": {
+            uri: AUTH_TOKEN,  # Token
         },
     }
     auth_headers = {