Deduplicate memories existing by external sources

[Josh-XT]

This pull request includes a significant update to the agixt/Memories.py file, specifically enhancing the write_text_to_memory function to handle duplicate content from external sources. The most important changes are:

Enhancements to duplicate content handling:

• Added logic to check for duplicates from external sources such as files or URLs. If a duplicate is found, the existing content from that source is deleted before writing the new content. This ensures that the memory does not contain redundant information.