[DirectX] Move isValidXYZ functions from BinaryFormat/DXContainer.h to BinaryFormat/DXContainer.cpp

[joaosaffran]

DirectX backend depends on a series of functions that follow the pattern isValid..., those are called when reading data from Metadata and Binary representation of Root Signatures. Those are currently inline inside BinaryFormat/DXContainer.h. This increases the size of the file, and is included multiple times, possibly slowing compilation. This issue aims to refactor this and only declare those functions in BinaryFormat/DXContainer.h and move their implementation to BinaryFormat/DXContainer.cpp, the same as getSampleFilter defined in the same file.

Originally requested here: #154631 (comment)