MSVC: Embed manifests directly for non-incremental vs_link_exe links

This avoids the need to separately execute "mt.exe" to perform the embedding of manifests into the output for non-incremental links. The primary motivation for this change is that this separate execution of "mt.exe" to embed manifests is known to cause intermittent failures due to AV/security scanning.

The only change in behaviour is that any linker generated manifest will no longer be output as a separate manifest file alongside the output file.

Fixes: #24531 (closed)