fix(instrumentation-redis): add spans for cluster multi/transaction commands

[Renegade2345]

Which problem is this PR solving?

When using createCluster (Redis cluster mode), commands run inside multi().exec() transactions do not produce OpenTelemetry spans. The same commands work correctly with createClient (standalone mode).
Fixes #3369

Short description of the changes

The existing instrumentation only patches the standalone Redis client's
multi-command module (client/multi-command.js). The cluster client uses
a separate multi-command class (cluster/multi-command.js) with a
different addCommand signature: (firstKey, isReadonly, args, transformReply)
vs the standalone (args).

This PR adds instrumentation for two additional module files:

• cluster/index.js — patches MULTI to store cluster options on the
  returned multi command object, so connection attributes are available
  when creating spans
• cluster/multi-command.js — patches addCommand and exec to create
  spans for each command in the transaction, mirroring the existing
  standalone client patching

A new test file test/v4-v5/redis.cluster.test.ts is added with tests
that require a live Redis cluster (gated behind RUN_REDIS_CLUSTER_TESTS
env var), covering:

• multi().exec() transaction commands producing spans
• multi().addCommand([...]).exec() generic command spans
• Error handling in cluster multi commands
• Regular cluster commands still producing spans

[github-actions]

This package does not have an assigned component owner and is considered unmaintained. As such this package is in feature-freeze and this PR will be closed with 14 days unless a new owner or a sponsor (a member of @open-telemetry/javascript-approvers) for the feature is found. It is the responsibility of the author to find a sponsor for this feature.
Are you familiar with this package? Consider becoming a component owner.

[Renegade2345]

Hey @blumamir, when you have time could you please review the changes? Any suggestions, corrections are more than welcome. Thanks!

[Renegade2345]

Hi @blumamir, could you please approve the workflow runs when you get a chance? Happy to make any changes if needed. Thanks!

[Renegade2345]

Hi @david-luna ,

Apologies for the ping, I wanted to follow up on this PR since it’s been open for a couple of weeks.
Since this package is currently unmaintained and the PR is at risk of auto-closing, could you please:

• Take a quick look if possible
• Approve the workflows so CI can run

Happy to make any changes or adjustments needed. Thanks a lot!

[david-luna]

@Renegade2345

Sorry I won't have the bandwith this week to have a look but I can give sponsorship and review the next one.

[Renegade2345]

No worries at all, completely understand!

Really appreciate you sponsoring this.
I’ll work on addressing the failing checks and improving coverage in the meantime. Happy to incorporate any feedback whenever you get a chance later. Thanks again!

[david-luna]

LGTM