Default to `internal_error` rather than `unknown_error` when setting error span status

[Lms24]

Description

Currently, we have some places in which we default to 'unknown_error' for the span status message if the span status is changed to Error (2). The message has the implication that the Sentry product does not render the span as errored. Therefore we decided to just default to 'internal_error' in all cases, except for a remaining case when determining error state from http response codes. This should make the intention of the 'unknown_error' more clear so that we don't accidentally default to it in the future.

[linear]

JS-1003 Default to `internal_error` rather than `unknown_error` when setting error span status