Improve performance of /xb/api/v0/config/component

This was causing cypress fails for me locally due to the time out.

MR improves performance by 80%

Salacious title update

Yep, I knew this: #3515510-2: Improve backend API performance: add caching to shape matching → 👈 that's why I moved it to the issue queue component :) This essentially does exactly what I intended 😃

There's plenty more low-hanging fruit, see https://git.drupalcode.org/project/experience_builder/-/merge_requests/1....

There's also 📌 [PP-1] Refactor GeneratedFieldExplicitInputUxComponentSourceBase and FieldForComponentSuggester to need only SDC's ComponentMetadata, not SDC plugin instances Postponed to decouple this from SDCs.

But here's the real kicker: we don't need any of this until a ContentTemplate UI exists! So I've been wanting to remove dynamic_prop_sources from the /xb/api/v0/config/component response for a good while. Which is why 📌 Move `PropSourceEndpointTest` into new `XbConfigEntityHttpApiTest::testComponent()` Active has been assigned to me for months. That will simply remove these computations from the critical path!

Because the ContentTemplate UI should be able to just request the candidate dynamic prop sources on a per-content entity-t bundle basis. There's never a need to list them all across all entity types/bundles — I did that only for early PoC/testing purposes!

Done: #3510896-8: Remove candidate `DynamicPropSource`s from `/xb/api/v0/config/component` to a new internal HTTP API for `ContentTemplate`s instead of → .

Next performance improvement: #3510896-8: Remove candidate `DynamicPropSource`s from `/xb/api/v0/config/component` to a new internal HTTP API for `ContentTemplate`s instead of → .