[clang] [analyzer] Ignore [[clang::flag_enum]] enums in the EnumCastOutOfRange checker (PR #141232)

[Gábor Horváth via cfe-commits]

https://github.com/Xazax-hun commented:

Should we still warn if we store a negative value or a value >= 2*last member?

https://github.com/llvm/llvm-project/pull/141232