Fix Hello Triangle Breathing example not working properly

[Mcgode]

time is declared on the stack, but was accessed through a pointer after being unscoped when calling rpsRenderGraphUpdate(). It resulted in receiving an invalid value in DrawTriangleBreathingCb, breaking the demo.

This PR fixes the issue by moving the local variable declaration to the same scope as rpsRenderGraphUpdate().

[FlorianHerickAMD]

Thank you for reporting this. We will address this either as part of a small maintenance update or the next version.