Add the missing dependency on gMock for GYP build.
Add the missing dependency on gMock for GYP build.

This fixes the build break on Kokoro.

PiperOrigin-RevId: 480769947

google/mozc,google/mozc,fcitx/mozc,fcitx/mozc,google/mozc,google/mozc,fcitx/mozc,fcitx/mozc,google/mozc,fcitx/mozc