feat(filters): add months filter to Twitch sub event (#3498)

[CathieNova]

Description of the Change

Added "Months Subbed" filter to the "Sub (Twitch)" event for more flexibility with sub alerts.

The Twitch sub event already passes totalMonths and streak into the twitch:sub event, but totalMonths was not available as a filter.

The filter supports number comparisons:
"is", "is not", "less than", "less than or equal to", "greater than", and "greater than or equal to".

Applicable Issues

#3498

Testing

Tested the filter both live and offline.

Confirmed:

• Firebot launches and runs normally
• The filter appears for the "Sub (Twitch)" event
• The filter settings save correctly
• The filter works as intended in a test build
• Sub events process correctly with the filter enabled

Screenshots

[zunderscore]

This is great, thanks!