Refactor DI for simplicity and type safety

This commit improves the dependency injection mechanism by introducing a
custom `injectKey` function.

Key improvements are:

- Enforced type consistency during dependency registration and
  instantiation.
- Simplified injection process, abstracting away the complexity with a
  uniform API, regardless of the dependency's lifetime.
- Eliminated the possibility of `undefined` returns during dependency
  injection, promoting fail-fast behavior.
- Removed the necessity for type casting to `symbol` for injection keys
  in unit tests by using existing types.
- Consalidated imports, combining keys and injection functions in one
  `import` statement.

tests/unit/presentation/components/Scripts/View/Tree/TreeView/UseCurrentTreeNodes.spec.ts

@@ -70,7 +70,7 @@ function mountWrapperComponent(treeWatcher: WatchSource<TreeRoot | undefined>) {
     {
       global: {
         provide: {
-          [InjectionKeys.useAutoUnsubscribedEvents as symbol]:
+          [InjectionKeys.useAutoUnsubscribedEvents.key]:
             () => new UseAutoUnsubscribedEventsStub().get(),
         },
       },