Not patch code attributes if the input is not function or method

[wangzlei]

Issue #, if available:

When a Starlette user registers an ASGI app via the route registration method, the ADOT Python SDK’s Starlette instrumentation mistakenly treats it as a regular synchronous function. As a result, the patched ASGI app cannot be properly registered in Starlette, preventing Starlette from starting the app. This leads clients to receive 405 Method Not Allowed errors.

Since FastMCP registers ASGI apps with Starlette, this bug causes MPC services built with FastMCP to fail to start.

Description of changes:
The PR contains 2 changes:

1. When the Code Attributes wrapper receives a callable that is neither a function nor a method, the ADOT Python SDK leaves it unmodified.
2. Code Attributes is off by default as an experimental feature. Users can enable the by environment variable OTEL_AWS_EXPERIMENTAL_CODE_ATTRIBUTES=true

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[vastin]

The contract tests failed and need to be updated because code attribute feature is disabled by default.