Fix FalkorDB sanitize to handle forward slash character

[david-morales]

Summary

• Fixes RediSearch query syntax errors when entity names contain forward slashes
• Adds / to the separator map in FalkorDB's sanitize() method

Problem

When entity names contained forward slashes (e.g., "Cruise / En route"), RediSearch queries were failing with syntax errors because the forward slash was not being sanitized. This resulted in malformed queries like:

(@group_id:\_) (Cruise | / | En | route)

Solution

Added / to the separator_map in the sanitize() method (line 324 in falkordb_driver.py), treating it like other special characters by replacing it with whitespace.

Now "Cruise / En route" is sanitized to "Cruise En route", which produces valid RediSearch queries.

Testing

Verified that:

• "Cruise / En route" → "Cruise En route"
• "Landing/Taxi" → "Landing Taxi"
• Multiple slashes are handled correctly

Fixes data insertion issues when using FalkorDB backend with forward slash characters in entity names.