Replace "(const override)" with "(const, override)" in GMOCKs

Just applied a short sed script. See bug description for
the motiviation for this change.

This is the command that was used to generate the changes:
$ find . -type f \( -iname '*.cc' -o -iname '*.h' \) -print0 | \
      xargs -0 sed -i -e 's/(const override)/(const, override)/'

Bug: webrtc:13090
Change-Id: Iec7d280f9d55263a972dbb3bd644ebfcd2eb38cf
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/249088
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Ali Tofigh <alito@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35801}

modules/audio_processing/agc2/vad_wrapper_unittest.cc

@@ -40,7 +40,7 @@ constexpr int kSampleRate8kHz = 8000;
 
 class MockVad : public VoiceActivityDetectorWrapper::MonoVad {
  public:
-  MOCK_METHOD(int, SampleRateHz, (), (const override));
+  MOCK_METHOD(int, SampleRateHz, (), (const, override));
   MOCK_METHOD(void, Reset, (), (override));
   MOCK_METHOD(float, Analyze, (rtc::ArrayView<const float> frame), (override));
 };