FEAT(client): Restore RNNoise for version 0.2

Added the git submodule from xiph/rnnoise after removing ReNameNoise.
Chose to go with `main` here. This commit follows the revert to
ReNameNoise.

Resolves #6395

Remove extra rnnoise submodule section

.gitmodules

@@ -28,9 +28,6 @@
 [submodule "3rdparty/cmake-compiler-flags"]
  path = 3rdparty/cmake-compiler-flags
  url = https://github.com/Krzmbrzl/cmake-compiler-flags.git
-[submodule "3rdparty/rnnoise-src"]
- path = 3rdparty/rnnoise-src
- url = https://github.com/xiph/rnnoise.git
 [submodule "3rdparty/flag-icons"]
  path = 3rdparty/flag-icons
  url = https://github.com/lipis/flag-icons.git