Restrict versions of opentelemetry-util-genai in vertex/google-genai instrumentations

[aabmass]

Description

Fixes #3786

We can increase the version range as needed, but this locks things down for now opentelemetry-util-genai is not stable.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

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

• Updated requirements.oldest.txt to test with the versions from PyPI.

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

[aabmass]

Here's the versions being used in each tox env now 🙂

Virtualenv	Version
lint-util-genai	0.3b0.dev0
py313-test-genai-util	0.3b0.dev0
py313-test-instrumentation-google-genai-latest	0.3b0.dev0
py313-test-instrumentation-google-genai-oldest	0.2b0
py313-test-instrumentation-vertexai-latest	0.3b0.dev0
py313-test-instrumentation-vertexai-oldest	0.2b0
typecheck	0.3b0.dev0