Adds support for passing in an optional injector when creating an embedded view through `ViewContainerRef.createEmbeddedView` and `TemplateRef.createEmbeddedView`. The injector allows for the DI behavior to be customized within the specific template.
This is a second stab at the changes in #44666. The difference this time is that the new injector acts as a node injector, rather than a module injector.
Fixes#14935.
PR Close#45156