Patch existing entities in POST /bundle/import

[frenchy64]

Epic https://github.com/advthreat/iroh/issues/7341
Related https://github.com/advthreat/iroh/issues/8207

Current behavior of bundle import on existing entities is to ignore them. This PR changes behavior to patch in this case, and loosens the schema for bundle import so then partial entities are allowed if patching.

§ QA

This PR adds the ability for POST /bundle/import to patch entities. The following steps test if this procedure works.

1. Create an existing entity (for example an Indicator) and note its id.
2. Patch this entity using POST /bundle/import. For example, patching the :producer field of the indicator:

POST /bundle/import?patch-existing=true
{:indicators [{:id "<id-from-step-1>" :producer "PATCHED"}]}

3. Verify that the result looks something like this (the "updated" part is the most important part):

{:results [{:result "updated" :id "<id-from-step-1>"}]}

4. Look up the indicator via GET /ctia/indicator to verify that the producer field was updated.

§ Release Notes

intern: Patch existing entities in POST /bundle/import

§ Squashed Commits

[ereteog]

LGTM

That's a very sensitive PR, it would be nice to extend the QA section with the merge strategy for asset properties and dedicated tests to actively test the scenario behind this PR with score update.

[ereteog]

🟠 why did you need to use the http layer (+ authorization) instead of the existing bundle/import?

[frenchy64]

I couldn't figure out how to make the test run on my machine.

[ereteog]

I guess that's now it's already included in the first test of the loop, right?:

           entities (loop [asset_refs asset_refs
                          entities {}]
                     (if (empty? asset_refs)
                       entities

[frenchy64]

I just left it in to skip a useless log.