WS-601: addresses bug in additional_metadata section of image manifest

This MR addresses bug in additional_metadata section of manifest that has a class repr rather than a JSON-serializable value

• tests dump all JSON strings; if dumps succeed, the JSON is good
• removed contrived test case
• added test case based on what an image ingestion staging dir is likely to contain

TODO next MR: implement additional tests for new image ingestion test case

apps/cli/executables/pexable/ingest_envoy/ingest_envoy/std_img_manifest_utils.py

@@ -87,29 +87,6 @@ class ImageIngestionProductsFinder:
             ),
         ]
 
-        # ancillary_products = []
-        # try:
-        #     ancillary_products.append(
-        #         AncillaryProduct(
-        #             type=AncillaryProductType.PIPELINE_WEBLOG_TYPE, filename=WEBLOG_FILENAME
-        #         )
-        #     )
-        # except ValueError as exc:
-        #     raise FileNotFoundError(f"No weblog found in {self.staging_source_dir}") from exc
-        #
-        # ancillary_files = [Path(ap.filename) for ap in ancillary_products]
-        #
-        # # find the pipeline artifacts tar
-        # pipeline_artifacts_tar = None
-        # for file in self.files_found:
-        #     if file not in ancillary_files and self._is_ancillary_image_product(file):
-        #         pipeline_artifacts_tar = file
-        # if pipeline_artifacts_tar:
-        #     pip_ap = AncillaryProduct(
-        #         type=AncillaryProductType.PIPELINE_ARTIFACTS, filename=pipeline_artifacts_tar.name
-        #     )
-        #     ancillary_products.append(pip_ap)
-
         return ancillary_products
 
     def _build_ancillary_image_science_product(self, file: Path):