OvmfPkg: Add duplicate exception for gUiAppFileGuid

gUiAppFileGuid, which is used to register EFI Firmware Config as a boot option,
has the same value as UiApp guid.

This would trigger a duplicate guid error from the CI pipeline, but because these
two guids are necessary, this commit adds a duplicate exception.

Signed-off-by: Luigi Leonardi <leonardi@redhat.com>

OvmfPkg/OvmfPkg.ci.yaml

@@ -81,7 +81,7 @@
         "IgnoreGuidName": ["ResetVector", "XenResetVector"], # Expected duplication for gEfiFirmwareVolumeTopFileGuid
         "IgnoreGuidValue": [],
         "IgnoreFoldersAndFiles": [],
-        "IgnoreDuplicates": ["gGrubFileGuid=Grub"],
+        "IgnoreDuplicates": ["gGrubFileGuid=Grub", "gUiAppFileGuid=UiApp"],
     },
 
     ## options defined .pytool/Plugin/LibraryClassCheck