Add appointment and object variable to wc_twilio_sms_appointments_token_map filter

[Valentina R]

This is the original filter:

$token_map = (array) apply_filters( 'wc_twilio_sms_appointments_token_map', $token_map );

It would be very useful to change it to:

$token_map = (array) apply_filters( 'wc_twilio_sms_appointments_token_map', $token_map, $appointment, $order );

so that customers can potentially add some other field if they need to.

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Needed here.

[Željan Topić]

Added with 4.9.6