Core/Misc: Fix static analysis issues

Fix various coverity reported issues

(cherry picked from commit 925557d1c097cd45311b38dc3a9c715579456980)

src/server/game/Entities/Player/Player.cpp

@@ -16476,6 +16476,7 @@ void Player::RemoveRewardedQuest(uint32 questId, bool update /*= true*/)
 
     // Remove seasonal quest also
     Quest const* qInfo = sObjectMgr->GetQuestTemplate(questId);
+    ASSERT(qInfo);
     if (qInfo->IsSeasonal())
     {
         uint16 eventId = qInfo->GetEventIdForQuest();

src/server/game/Maps/Map.cpp

@@ -2943,8 +2943,10 @@ void Map::GetFullTerrainStatusForPosition(PhaseShift const& phaseShift, float x,
     if (vmapData.areaInfo)
         data.areaInfo = boost::in_place(vmapData.areaInfo->adtId, vmapData.areaInfo->rootId, vmapData.areaInfo->groupId, vmapData.areaInfo->mogpFlags);
 
+    float mapHeight = VMAP_INVALID_HEIGHT;
     GridMap* gmap = GetGrid(terrainMapId, x, y);
-    float mapHeight = gmap->getHeight(x, y);
+    if (gmap)
+        mapHeight = gmap->getHeight(x, y);
 
     // area lookup
     AreaTableEntry const* areaEntry = nullptr;