Rename PyPI distribution to openobserve-python-sdk

[uddhavdave]

Change

• Rename the PyPI distribution to openobserve-python-sdk while keeping import openobserve unchanged.
• Update installation examples and gRPC guidance.
• Keep the broken-exporter test focused on the actual import failure rather than exact message wording.

Verification

• Built openobserve_python_sdk-0.2.0-py3-none-any.whl and installed it in an isolated environment; metadata and both openobserve and openobserve._eval imports succeeded.
• uv run --no-project --with pytest --with-editable . pytest -q tests/test_broken_transport.py: 3 passed.

Publishing remains tag-triggered by .github/workflows/ci.yml. The first upload under the new PyPI name needs credentials authorized to create that project.