[bug] ID returned when ingesting packages is incorrect

[jeffmendoza]

Describe the bug
When ingesting packages, the ID returned is the top-level ID (package type) and not the lowest level ID (package version)

https://github.com/guacsec/guac/blob/main/pkg/assembler/graphql/resolvers/package.resolvers.go#L19
https://github.com/guacsec/guac/blob/main/pkg/assembler/graphql/resolvers/package.resolvers.go#L28

To Reproduce

Ingest packages using GQL, note id returned

Expected behavior
Should be the lowest level ID (package version node id)

GUAC version
head

[jeffmendoza]

Note, whenever we change the backend interface to return ID and not extract it here in the resolver, this code will be obsoleted.

[pxp928]

This was also caught in the PR by @knrc. This is changing to now return a flat struct of pkg IDs: #1367 (comment)