CuratedPackage: Ensure toUncuratedPackage() clears the concluded license

The data model of `PackageCurationResult` is ambiguous. It is not
possible to derive the original concluded license from the list of
`PackageCurationResult`s even if `Package.diff()` was adjusted to handle
the concluded license, see also [1].

Work around that issue by just clearing the concluded license.

[1] #5637

Signed-off-by: Frank Viernau <frank_viernau@epam.com>

model/src/main/kotlin/CuratedPackage.kt

@@ -54,7 +54,13 @@ data class CuratedPackage(
             curation.base.apply(current)
         }.pkg.copy(
             // The declared license mapping cannot be reversed as it is additive.
-            declaredLicensesProcessed = DeclaredLicenseProcessor.process(pkg.declaredLicenses)
+            declaredLicensesProcessed = DeclaredLicenseProcessor.process(pkg.declaredLicenses),
+
+            // It is not possible to derive the original concluded license value with the above reversed application
+            // of the base curations, even if the function Package.diff() was extended to handle the concluded license,
+            // see also https://github.com/oss-review-toolkit/ort/issues/5637. Until this is fixed just set the
+            // concluded license to null, because an un-curated package cannot have a non-null concluded license.
+            concludedLicense = null
         )
 
     @JsonIgnore