feat(telemetry, extensibility): add joule_studio_gsid to extension context and span

[rishikunnath2747]

Disclaimer: Do not include SAP-internal or customer-specific information in this PR (e.g. internal system URLs, customer names, tenant IDs, or confidential configurations). This is a public repository.

Description

Adds Joule Studio GSID (joule_studio_gsid) as a first-class field alongside solution_id throughout the extension telemetry pipeline.

• Define ATTR_JOULE_STUDIO_GSID constant in extensions.py and export it from the telemetry package init
• Add joule_studio_gsid parameter to extension_context(), with baggage propagation and log filter support matching solution_id behaviour
• Add joule_studio_gsid to build_extension_span_attributes() as a conditional span attribute (omitted when empty)
• Add joule_studio_gsid field to ExtensionSourceInfo dataclass and parse it from the UMS GraphQL response (jouleStudioGsid)
• Rename ATTR_GLOBAL_SOLUTION_ID → ATTR_JOULE_STUDIO_GSID for consistency with the field name
• Extend test_extensions.py to cover joule_studio_gsid in all tests that already cover solution_id

Type of Change

Please check the relevant option:

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Code refactoring
• Dependency update

Checklist

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• I have read the Contributing Guidelines
• I have verified that my changes solve the issue
• I have added/updated automated tests to cover my changes
• All tests pass locally
• I have verified that my code follows the Code Guidelines
• I have updated documentation (if applicable)
• I have added type hints for all public APIs
• My code does not contain sensitive information (credentials, tokens, etc.)
• I have followed Conventional Commits for commit messages