fix(pre-init): put unresolved method path on stackTrace

[rmi22186]

Summary

• When a pre-init ready-queue method fails to resolve, put the method path on the error stack (e.g. mParticle pre-init method not found: Identity.login) and forward it via stackTrace from identityApiClient so Datadog can query it.
• Keep the error message low-cardinality (Unable to compute proper mParticle function - method not found) so existing monitors still match the shared prefix.
• Separate unresolved methods from resolved methods that throw, so those two failure modes are no longer collapsed into the same TypeError-from-.apply shape.

Why

~947k of the recent IDENTITY_REQUEST / Unable to compute proper mParticle function errors were single-wrap failures where Datadog could not show which queued method failed (StackTrace: null, no method in the message). Partner investigation (Wingstop) showed the high-volume case was largely the pre-2.73.0 item-mutation bug reading an argument as the method name — but without a method path on the report we could not confirm that from telemetry alone.

Test plan

• Jest: unresolved method throws the new message
• Jest: method path is present on error.stack
• Jest: resolved method that throws still uses the existing wrapper message
• Jest: non-function property treated as unresolved
• npm run lint
• After merge/deploy: Datadog @errorInfo.StackTrace (or equivalent) contains mParticle pre-init method not found: <path> for unresolved methods
• Confirm existing monitors on Unable to compute proper mParticle function still match the new - method not found suffix

[cursor]

PR Summary

Low Risk
Changes are limited to pre-init queue error handling and identity error reporting metadata; no auth or API behavior changes.

Overview
Improves observability when the pre-init ready queue cannot resolve a dotted method (e.g. Identity.login): failures now throw a stable, low-cardinality message (Unable to compute proper mParticle function - method not found) while the queued method path is recorded on the error stack (mParticle pre-init method not found: <path>). Resolution uses optional chaining and an explicit function check, so missing namespaces no longer show up as incidental TypeErrors, and that case is separate from a method that resolved but threw during execution.

Identity request error reporting now includes stackTrace from the caught error so Datadog (and similar) can query stack content instead of seeing StackTrace: null for wrapped pre-init failures.

Jest coverage was expanded for stack content, resolved-vs-unresolved failures, and non-function properties treated as unresolved.

^{Reviewed by Cursor Bugbot for commit ac53dd8. Bugbot is set up for automated code reviews on this repo. Configure here.}

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud