Handle fire of DETECTED_SPEECH events using a global variable

[bundasmanu]

At this point, we can only handle the fire of DETECTED_SPEECH events, by setting fire_asr_events in the channel.

This works, but its not feasible, if we want to fire the events always and for all channels.

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So, in this PR, it was introduced a logic that:

• Allows the fire of DETECTED_SPEECH events if fire_asr_events is setted as a global var;
• The remaining logic was kept as is;
  • If we don't have the global var setted, the channel check for fire_asr_events is done;

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Tests:

Oh, yes.

• global var and channel var not setted;
  • Events not fired;
• channel var setted to true:
  • Events fired;
• Global var setted to true:
  • Events fired;