Fix shim docstring example

[Manvi2402]

Description

Fix incorrect code example in create_tracer() docstring.

The docstring example was passing a Tracer object to create_tracer(),
but it expects a TracerProvider object.

Fixes #5072

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

No tests required — this is a documentation-only fix (docstring example).
Existing test in test_shim.py:46 already validates correct usage.

Does This PR Require a Contrib Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated