fix duplicate bytes clearing + makes iast key present in snapshots

Author: e-n-0

tracer/test/Datadog.Trace.Security.IntegrationTests/IAST/AspNetCore5IastTests.cs

@@ -414,11 +414,6 @@ public async Task TestVulnerabilityStack(string name, string url)
                     var json = MetaStructToJson(data);
                     span.Tags["_dd.stack"] = json;
                 }
-
-                foreach (var key in span.MetaStruct.Keys.ToArray())
-                {
-                    span.MetaStruct[key] = [];
-                }
             }
         }
 

tracer/test/Datadog.Trace.Security.IntegrationTests/IAST/IastVerifyScrubberExtensions.cs

@@ -94,8 +94,6 @@ public static void IastMetaStructScrubbing(MockSpan target, bool forceMetaStruct
                 var json = JsonConvert.SerializeObject(iastMetaStruct, Formatting.Indented);
                 target.Tags[Tags.IastJson] = json;
 
-                target.MetaStruct.Remove("iast");
-
                 // Let the snapshot know that the data comes from the meta struct
                 if (forceMetaStruct)
                 {