LBR must typehint interface rather than a specific implementation

Problem/motivation

Just like all of the ModuleHandler interface issues referenced by this issue: #3277301: Adapt to centralised hook dispatcher in Drupal 9.4

Both EntityTypeManagerInterface and RendererInterface are typehinted with their default/concrete implementation, rather than an interface. Additionally, there are incorrect doc typehinting in the same line.

This prevents other code from changing the Renderer and EntityTypeManager services by changing their default class or by using service decoration, in the case of Pinto Theme in my case.

Combined, when loading the AllowedBlocksForm form, a fatal exception is thrown.

Steps to repro

Install and enable layout_builder_restrictions_by_region + pinto_theme

Load the AllowedBlocksForm form

See: error 500

Proposed resolution

Change to interfaces as is standard.