[BUG]: Chat with your documents example exhibits flaky retrieval (#1203)

## Description of changes

*Summarize the changes made by this PR.*
In #1115 @BChip noticed
flaky retrieval performance.

The issue was difficult to replicate because of nondeterminism inherent
in the HNSW graph construction on loading, but I was able to track it
down through repeated testing.

The issue is caused by ingesting all the empty lines in the document,
which make up 50% of all the lines in each file, which outputs the same
embedding for all of them, causing the HNSW graph to sometimes be
degenerate.

The fix is to skip the empty lines. We should consider how we can
mitigate this in the future since this is not easy to detect after the
fact, and is likely to be something users run into.

## Test plan

Failures no longer occur after manual invocation. 

## Documentation Changes
N/A

examples/chat_with_your_documents/load_data.py

@@ -22,6 +22,9 @@ def main(
             ):
                 # Strip whitespace and append the line to the documents list
                 line = line.strip()
+                # Skip empty lines
+                if len(line) == 0:
+                    continue
                 documents.append(line)
                 metadatas.append({"filename": filename, "line_number": line_number})