python: remove TaintStepFromSummary

as it should be covered by `SummarizedCallableFromModel`

Also move things around, to look more like the Ruby code.

python/ql/lib/semmle/python/dataflow/new/FlowSummary.qll

@@ -2,7 +2,6 @@
 
 private import python
 private import semmle.python.dataflow.new.DataFlow
-private import semmle.python.frameworks.data.ModelsAsData
 private import semmle.python.ApiGraphs
 private import internal.FlowSummaryImpl as Impl
 private import internal.DataFlowUtil
@@ -11,6 +10,7 @@ private import internal.DataFlowPrivate
 // import all instances below
 private module Summaries {
   private import semmle.python.Frameworks
+  private import semmle.python.frameworks.data.ModelsAsData
 }
 
 deprecated class SummaryComponent = Impl::Private::SummaryComponent;
@@ -36,32 +36,3 @@ abstract class SummarizedCallable extends LibraryCallable, Impl::Public::Summari
 }
 
 deprecated class RequiredSummaryComponentStack = Impl::Private::RequiredSummaryComponentStack;
-
-private class SummarizedCallableFromModel extends SummarizedCallable {
-  string type;
-  string path;
-
-  SummarizedCallableFromModel() {
-    ModelOutput::relevantSummaryModel(type, path, _, _, _) and
-    this = type + ";" + path
-  }
-
-  override CallCfgNode getACall() { ModelOutput::resolvedSummaryBase(type, path, result) }
-
-  override ArgumentNode getACallback() {
-    exists(API::Node base |
-      ModelOutput::resolvedSummaryRefBase(type, path, base) and
-      result = base.getAValueReachableFromSource()
-    )
-  }
-
-  override predicate propagatesFlow(string input, string output, boolean preservesValue) {
-    exists(string kind | ModelOutput::relevantSummaryModel(type, path, input, output, kind) |
-      kind = "value" and
-      preservesValue = true
-      or
-      kind = "taint" and
-      preservesValue = false
-    )
-  }
-}