MdeModulePkg/HiiDatabaseDxe: Fix potential intrinsic error

In some VS22 versions, these code patterns (assiging the scalar in
a loop) have been found to be converted into calls to the `memcpy`
intrinsic. This change updates them to use CopyMem to avoid the
potential error.

Previous:
- MSVC version: 14.31.31103

New:
- MSVC version: 14.32.31326

Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>