Revert "[audio] Replace libopus with FFmpeg (#4169)" (#4419)

This reverts commit ff8368c606.

- [x] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions).
- [x] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md)
- [x] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability.

-------------------

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4419
Reviewed-by: Maufeat <sahyno1996@gmail.com>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

CMakeLists.txt

@@ -464,6 +464,21 @@ if (NOT YUZU_STATIC_ROOM)
     if (ZLIB_ADDED)
         add_library(ZLIB::ZLIB ALIAS zlibstatic)
     endif()
+
+    # Opus
+    AddJsonPackage(opus)
+
+    if (Opus_ADDED)
+        if (MSVC AND CXX_CLANG)
+            target_compile_options(opus PRIVATE
+                $<$<COMPILE_LANGUAGE:C,CXX>:-Wno-implicit-function-declaration>
+            )
+        endif()
+    endif()
+
+    if (NOT TARGET Opus::opus)
+        add_library(Opus::opus ALIAS opus)
+    endif()
 endif()
 
 if(NOT TARGET Boost::headers)