Address inconsistent datatypes in vk.py

Changing datatypes for optimalTilingLayoutUUID, pipelineCacheUUID and
size_t. optimalTilingLayoutUUID and pipelineCacheUUID are arrays of size
VK_UUID_SIZE. size_t is a large number that can be represented with
ctypes.c_uint64 but not int.

Flag: NONE infeasible
Bug: b/408169111
Test: N/A

Change-Id: I0b46fd9e0aead2d5610fa8f4e2ef9e6a302c8365