Fix json_ready_sym to serialize actual attribute values instead of boolean True

[code-uri]

The json_ready_sym function in src/events/events.py was incorrectly serializing all truthy symbol attributes as True in the JSON output. This caused critical data loss for attributes that carry numerical values, such as multiplier (e.g., a multiplier of 10 was being output as "multiplier": true).

math-sdk/src/events/events.py

Line 14 in 457a69a

print_sym[attr] = True