Draft: Enforce TaggerType enum usage

Following discussion in !4986 (merged)

Event/EventPacker/src/lib/PackedFlavourTag.cpp

@@ -40,7 +40,7 @@ void FlavourTagPacker::pack( const Data& ft, PackedData& pft, PackedDataVector&
     auto& ptagger = pfts.taggers().emplace_back();
 
     // save data members
-    ptagger.type     = T.type();
+    ptagger.type     = static_cast<decltype( ptagger.type )>( T.type() );
     ptagger.decision = to_underlying( T.decision() );
     ptagger.omega    = StandardPacker::fraction( T.omega() );
 
@@ -102,7 +102,7 @@ StatusCode FlavourTagPacker::unpack( const PackedData& pft, Data& ft, const Pack
     auto& tagger = taggers.emplace_back();
 
     // set the tagger members
-    tagger.setType( ptagger.type );
+    tagger.setType( static_cast<Tagger::TaggerType>( ptagger.type ) );
     tagger.setDecision( Tagger::TagResult{ ptagger.decision } );
     tagger.setOmega( StandardPacker::fraction( ptagger.omega ) );