openai-v2: handle NotGiven values in request parameters

[xrmx]

Description

This PR filters out attributes where the value is NOT_GIVEN or not_given form the llm_request_attributes dictionary. These values cannot be set as an attribute value and should be treated as equivalent to None.

This warning message is generated in opentelemetry.attributes here.

Example WARNING log:

WARNING  opentelemetry.attributes:__init__.py:111 Invalid type NotGiven for attribute 'top_p' value. Expected one of ['bool', 'str', 'bytes', 'int', 'float'] or a sequence of those types

Fixes #3921
Closes #3760

This is on top of #3760 but generalizes it and add tests for embeddings. While at it I've bumped the openai version in latest test requirement to latest available < 2 and added a README.md for documenting how to configure tox to let the OPENAI_API_KEY environment variable pass. No idea why I had to add datalib optional dependencies to the oldest requirements file.

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?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• tox

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

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