packages/openai: Update logo and the documentation

[shmsr]

Proposed commit message

Updated the OpenAI logo since OpenAI was rebranded in February and they now have a new logo. Also, updated the documentation to clearly explain that while we are collecting metrics that are stored in logs-*, although they are not logs. Many other integrations follow this practice, and to be consistent, we want to make sure the OpenAI package also does the same.

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.
• I have verified that any added dashboard complies with Kibana's Dashboard good practices

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: d021cbd

cc @shmsr

[alaudazzi]

LGTM

[elastic-vault-github-plugin-prod]

Package openai - 1.1.0 containing this change is available at https://epr.elastic.co/package/openai/1.1.0/