Rename entity bundle and target entity scope plugins for better DX
## Problem/solution
Follow up to:
#3586148+s
The naming of the entity bundle and target entity scope plugins is confusing.
## Solution
**AiContextScopeEntityBundle**
Rename Entity Bundle => Entity Type at a code-level because there are bundleless content entities.
Label: Entity Types
Description: Apply this context to every entity of a chosen type, for example all Article nodes, every Document media item, or every Canvas page. Choose this when the context is true for the whole type, not a single item.
**AiContextScopeTargetEntity**
Rename Target Entity => Entity Item because target shouldn't be part of the name and "instance" is too nerdy.
Label: Specific Entities
Description: Apply this context only to the entities chosen below, for example the 'About us' node or one particular Canvas page. Choose this when the context is unique to that item, not its type.
target_entities field: No label
## Tasks
- [ ] Update code
- [ ] Review code
- [ ] Test code
issue