MdeModulePkg:Fix the issue FindQuestionFromProgress in SetupBrowserDxe is broken

MdeModulePkg:Fix the issue FindQuestionFromProgress in SetupBrowserDxe is broken

If the storage of the question is EFI_HII_VARSTORE_BUFFER/EFI_HII_VARSTORE_EFI_VARIABLE_BUFFER,
in SetupBrowserDxe the configuration stings contain uppercase,but HiiDataBaseDxe generates the
ConfigResp string in lowercase,they mismatch,so FindQuestionFromProgress function is broken.
Now convert the configuration string in SetupBrowserDxe to lowercase to fix this issue.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18143 6f19259b-4bc3-4df7-8a09-765794883524