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/Code/CodeButtons/Save/Instructions/CodeInstruction.spec.ts

@@ -1,7 +1,7 @@
 import { describe, it, expect } from 'vitest';
 import { shallowMount } from '@vue/test-utils';
 import CodeInstruction from '@/presentation/components/Code/CodeButtons/Save/Instructions/CodeInstruction.vue';
-import { expectThrowsAsync } from '@tests/unit/shared/Assertions/ExpectThrowsAsync';
+import { expectThrowsAsync } from '@tests/shared/Assertions/ExpectThrowsAsync';
 import { InjectionKeys } from '@/presentation/injectionSymbols';
 import { Clipboard } from '@/presentation/components/Shared/Hooks/Clipboard/Clipboard';
 import { UseClipboardStub } from '@tests/unit/shared/Stubs/UseClipboardStub';
@@ -74,7 +74,7 @@ function mountComponent(options?: {
   return shallowMount(CodeInstruction, {
     global: {
       provide: {
-        [InjectionKeys.useClipboard as symbol]:
+        [InjectionKeys.useClipboard.key]:
           () => {
             if (options?.clipboard) {
               return new UseClipboardStub(options.clipboard).get();