qt6: remove 'noop' assignment

This also prevents Qt 6 builds failing with:
conversion from 'int' to 'QChar' is ambiguous

Author: Chiitoo

src/core/AdblockContentFiltersProfile.h

@@ -127,7 +127,7 @@ class AdblockContentFiltersProfile final : public ContentFiltersProfile
 			bool needsDomainCheck = false;
 		};
 
-		QChar value = 0;
+		QChar value;
 		QVarLengthArray<Node*, 1> children;
 		QVarLengthArray<Rule*, 1> rules;
 	};