[Remote] check subworkflows for launch plan nodes

[wild-endeavor]

Why are the changes needed?

Launch plans are not included in closures fetched from Admin because they always refer to and are defined by the ones in Admin. When FlyteRemote scans for launch plan definitions, it should scan for both the primary as well as any subworkflows.

What changes were proposed in this pull request?

In addition to the primary workflow template, also check subworkflow templates.

• Also add an lru cache to the get launch plan/wf/task call in the friendly clients, ideally we go through all the friendly client functions and cache all the ones that make sense to, but this determination should be done in a separate pr.
  • Note that the lru cache does not cache exceptions, so if the underlying entity is missing, it will not be cached.

How was this patch tested?

Tested against a live control plane.

Setup process

Screenshots

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Related PRs

Docs link