[Telephony] SerialNumberInput should handle dashes in user inputs

[stevengum]

Is your feature request related to a problem? Please describe.

The SerialNumberInput prompt should support a dashes in user inputs (e.g., "-" in "C66-T676").

When a user conveys the serial number "C66-T676" to a bot, they might do so in a series of responses with pauses between each input, like so:

User: C User: 6 User: 6 User: dash User: T User: 6 User: 7 User: 6

Whether or not the SerialNumberInput action aggregates a dash should be configured by the bot author. E.g., should the aggregated input be "C66-T676" or "C66T676"?

Ultimately, the processing of a dash should not result in a fail state for any user language, either through a bot throwing an exception or the user's correct input resulting in an failed aggregation.

Describe the solution you'd like

When a user provides a dash while relaying their serial number input to the bot, the SerialNumberInput action should not blow up and the final aggregated input should include the dash when configured by the bot author.

Describe alternatives you've considered

SerialNumberInput support dashes as a valid but non-aggregatable input, so that every bot using SerialNumberInput simply returns only alphanumeric inputs.

A user's input of "RRT-000001" is aggregated as "RRT000001".

This alternative approach is likely the better initial behavior to have for customers because its behavior is clear, understandable and static.

Additional context

In addition to unit and integration tests for the SerialNumberInput we will need to run manual tests with the Telephony channel to verify the E2E behavior is as intended.