Ignore converted datasets in invalid input states

Fixes a bug reported by @jennaj where using an input dataset from a history
import (which contains implicitly converted datasets in discarded state)
in an input that would require that exact same implicit conversion
would fail with `Job output deleted by user before job completed`.

This will make the whole implicit coversion system much more robust,
since we didn't even exclude datasets in error state, so as soon as one
conversion failed ... you'd be stuck.

lib/galaxy/model/__init__.py

@@ -4112,7 +4112,9 @@ class Dataset(Base, StorableObject, Serializable):
 
     non_ready_states = (states.NEW, states.UPLOAD, states.QUEUED, states.RUNNING, states.SETTING_METADATA)
     ready_states = tuple(set(states.__members__.values()) - set(non_ready_states))
-    valid_input_states = tuple(set(states.__members__.values()) - {states.ERROR, states.DISCARDED})
+    valid_input_states = tuple(
+        set(states.__members__.values()) - {states.ERROR, states.DISCARDED, states.FAILED_METADATA}
+    )
     no_data_states = (states.PAUSED, states.DEFERRED, states.DISCARDED, *non_ready_states)
     terminal_states = (
         states.OK,
@@ -4543,6 +4545,7 @@ class DatasetInstance(RepresentById, UsesCreateAndUpdateTime, _HasTable):
     creating_job_associations: List[Union[JobToOutputDatasetCollectionAssociation, JobToOutputDatasetAssociation]]
     copied_from_history_dataset_association: Optional["HistoryDatasetAssociation"]
     copied_from_library_dataset_dataset_association: Optional["LibraryDatasetDatasetAssociation"]
+    implicitly_converted_datasets: List["ImplicitlyConvertedDatasetAssociation"]
 
     validated_states = DatasetValidatedState
 
@@ -4870,9 +4873,9 @@ def display_info(self):
     def get_converted_files_by_type(self, file_type):
         for assoc in self.implicitly_converted_datasets:
             if not assoc.deleted and assoc.type == file_type:
-                if assoc.dataset:
-                    return assoc.dataset
-                return assoc.dataset_ldda
+                item = assoc.dataset or assoc.dataset_ldda
+                if not item.deleted and item.state in Dataset.valid_input_states:
+                    return item
         return None
 
     def get_converted_dataset_deps(self, trans, target_ext):