fix(active-record): avoid error spans for handled RecordInvalid

[aviralgarg05]

Summary

This PR fixes issue #1459 by preventing low-signal error spans for app-handled ActiveRecord bang persistence exceptions.

What changed

• save!, create!, and update! now close spans and re-raise configured handled exceptions outside the span.
• Default handled exception list remains narrow: [ActiveRecord::RecordInvalid].
• Added optional configuration: handled_exceptions, which can include entries like ActiveRecord::RecordNotFound when teams explicitly want that behavior.

Why this is in scope

• Default behavior still targets the original issue for RecordInvalid.
• Reviewer feedback about configurability is implemented without broadening defaults.

Tests

• RecordInvalid is suppressed for save!, create!, and update!.
• Non-handled exceptions still emit exception events.
• Configured handled exception behavior is covered by tests.

[dmathieu]

What about other errors that usually don't raise either, such as RecordNotFound?
Should the list of exceptions be configurable?

[aviralgarg05]

What about other errors that usually don't raise either, such as RecordNotFound? Should the list of exceptions be configurable?

Applied these as well

[github-actions]

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[arielvalentin]

Thank you for this contribution and patience. We are low on reviewing capacity recently so its taking me a while to get to changes like yours for a review.

I think that the way Rails allows flow and control through exception handling is a bit at odds with the guidance in the spec which recommends we should record an error if it is unhandled and set the span status to Error.

https://opentelemetry.io/docs/specs/otel/trace/exceptions/#recording-an-exception

Adding allow lists to a library in this way and then interrupting the flow control and re-raising seems like something we would want to centralized in the in_span helper or these methods should inline the in_span helper and only record unexpected exceptions.

I think we can also avoid the unnecessary comparisons in the handle_exception method if we explicitly handled them in rescue blocks.