fix: solve JDT Null Analysis Missmatch Error

Author: rubenporras

org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/symbols/LSPSymbolInWorkspaceDialog.java

@@ -230,10 +230,10 @@ private static List<WorkspaceSymbol> toWorkspaceSymbols(@Nullable List<? extends
 		return res;
 	}
 
-	static List<? extends WorkspaceSymbol> eitherToWorkspaceSymbols(
+	static List<@Nullable ? extends WorkspaceSymbol> eitherToWorkspaceSymbols(
 			final @Nullable Either<List<? extends SymbolInformation>, List<@Nullable ? extends WorkspaceSymbol>> source) {
 		return source == null //
-				? List.of()
-				: source.map(LSPSymbolInWorkspaceDialog::toWorkspaceSymbols, Function.identity());
+						? new ArrayList<@Nullable WorkspaceSymbol>()
+						: source.map(LSPSymbolInWorkspaceDialog::toWorkspaceSymbols, Function.identity());
 	}
 }