[PROF-5808] Add ENFORCE_TYPE as user-friendly alternative to Check_Type

[ivoanjo]

Motivation:

While investigating #2151, I realized that Check_Type's error message: TypeError: wrong argument type nil (expected String) is very hard to debug in functions that do many Check_Type verifications (such as _native_do_export).

What does this PR do?:

To fix this, I've created a new ENFORCE_TYPE helper which behaves similarly, but generates error messages such as:

TypeError: wrong argument nil for 'pprof_file_name' (expected a RUBY_T_STRING) at ../../../../ext/ddtrace_profiling_native_extension/http_transport.c:280:in `_native_do_export'

Hopefully this message will help us get to the bottom of the issue.

I've modified every other use of Check_Type in the profiling native extension to use this new helper, in case we need to debug similar issues in the future.

Additional notes:

This PR is on top of #2152 to facilitate testing both together, but is otherwise independent.

How to test the change?:

Existing tests should already cover this. To trigger the issue manually, use for instance:

[3] pry(main)> Datadog::Profiling::HttpTransport._native_do_export(nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil)
TypeError: wrong argument nil for 'upload_timeout_milliseconds' (expected a RUBY_T_FIXNUM) at ../../../../ext/ddtrace_profiling_native_extension/http_transport.c:275:in `_native_do_export'
from (pry):3:in `_native_do_export'

Issue #2151