[Python] Improve python API (#8781)

* Fix generate_code script path

* [Python] Make StartVector public

Make StartVector vector public since it is already being used in
generated code

* [Python] Improve vector creation for Python API

Makes Python API for vectors cleaner like Rust and Swift

---------

Co-authored-by: Derek Bailey <derekbailey@google.com>

python/flatbuffers/reflection/Schema.py

@@ -180,6 +180,12 @@ def SchemaStartObjectsVector(builder, numElems):
 def StartObjectsVector(builder, numElems):
     return SchemaStartObjectsVector(builder, numElems)
 
+def SchemaCreateObjectsVector(builder, data):
+    return builder.CreateVectorOfTables(data)
+
+def CreateObjectsVector(builder, data):
+    SchemaCreateObjectsVector(builder, data)
+
 def SchemaAddEnums(builder, enums):
     builder.PrependUOffsetTRelativeSlot(1, flatbuffers.number_types.UOffsetTFlags.py_type(enums), 0)
 
@@ -192,6 +198,12 @@ def SchemaStartEnumsVector(builder, numElems):
 def StartEnumsVector(builder, numElems):
     return SchemaStartEnumsVector(builder, numElems)
 
+def SchemaCreateEnumsVector(builder, data):
+    return builder.CreateVectorOfTables(data)
+
+def CreateEnumsVector(builder, data):
+    SchemaCreateEnumsVector(builder, data)
+
 def SchemaAddFileIdent(builder, fileIdent):
     builder.PrependUOffsetTRelativeSlot(2, flatbuffers.number_types.UOffsetTFlags.py_type(fileIdent), 0)
 
@@ -222,6 +234,12 @@ def SchemaStartServicesVector(builder, numElems):
 def StartServicesVector(builder, numElems):
     return SchemaStartServicesVector(builder, numElems)
 
+def SchemaCreateServicesVector(builder, data):
+    return builder.CreateVectorOfTables(data)
+
+def CreateServicesVector(builder, data):
+    SchemaCreateServicesVector(builder, data)
+
 def SchemaAddAdvancedFeatures(builder, advancedFeatures):
     builder.PrependUint64Slot(6, advancedFeatures, 0)
 
@@ -240,6 +258,12 @@ def SchemaStartFbsFilesVector(builder, numElems):
 def StartFbsFilesVector(builder, numElems):
     return SchemaStartFbsFilesVector(builder, numElems)
 
+def SchemaCreateFbsFilesVector(builder, data):
+    return builder.CreateVectorOfTables(data)
+
+def CreateFbsFilesVector(builder, data):
+    SchemaCreateFbsFilesVector(builder, data)
+
 def SchemaEnd(builder):
     return builder.EndObject()