NoPreference does not supercede Game default override

FrameRateCategory::NoPreference is similar to "no vote". If there is a
game default frame rate override, it should not supercede this.
For example, a game with 60 default frame rate override should get this
override even when Toolkit sends NoPreference on it.

Bug: 377169395
Flag: EXEMPT bugfix
Test: atest libsurfaceflinger_unittest
Test: manual test with game, it uses game default frame rate
Change-Id: Id773c03fdd32c3a55b19a6acac788aabf133ebfc