Ensure we handle the scenario the payment service code expects there to be an active span but finds none

[keyoke]

I am proposing a very minor change to handle when auto-instrumentation is disabled( similar to #2124 ) for the payment service. In this scenario, an exception is raised but I would expect it to be handled gracefully.

Changes

Added some very simple logic to check if the current active span is undefined, if it is we create a new span & mark this as the active span.

Merge Requirements

For new features contributions, please make sure you have completed the following
essential items:

• CHANGELOG.md updated to document new feature additions
• Appropriate documentation updates in the docs
• Appropriate Helm chart updates in the helm-charts

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.

[linux-foundation-easycla]

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• ✅ login: keyoke / name: GarethE (28e0d1a, 2f9eb59)

[julianocosta89]

@pichlermarc I would love to hear your opinion here