[BUG][LEXICAL-GRAPH] suppressed exceptions in the data loaders

[fbmz-improving]

Summary

There suppressed exceptions in the data loaders (pptx, etc..) metadata doesn’t have the expected format which is causing the lexical-graph processing to hang indefinitely.

Success Criteria

• pinpoint these suppressed exceptions
• filter out the malformed data before ingestion
• ensure that the notebooks finish properly without hanging

[acarbonetto]

see: "Custom Metadata Functions" in https://github.com/awslabs/graphrag-toolkit/blob/main/examples/lexical-graph-local-dev/notebooks/04-Advanced-Configuration-Examples.ipynb

[iansrobinson]

b2536cb moves collection-based metadata items to an invalid_metadata section prior to building
33880bc ensures that all reader providers raise appropriate ImportErrors if their dependencies are not installed
1ece3f9 ensures that unretriable Neptune queries error early
7f9f436 strips microseconds from metadata datetime values

[iansrobinson]

@acarbonetto If you get a chance, please would you rerun with the latest release (3.17.0). I'll also add an integration test that runs those advanced config examples against Neptune.