Add wake word phrase to voice assistant start command

[jesserockz]

What does this implement/fix?

This sends the on device wake word phrase to Home Assistant so it can then "block" multiple assistants from activating at the same time within a small timeframe.

Related PRs:

• ESPHome: Pass through wake_word_phrase from on-device microWakeWord home-assistant/core#111585
• Add wake_word_phrase to VoiceAssistant request aioesphomeapi#830

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

Related issue or feature (if applicable): fixes

Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#

Test Environment

• ESP32
• ESP32 IDF
• ESP8266
• RP2040
• BK72xx
• RTL87xx

Example entry for config.yaml:

# Example config.yaml
micro_wake_word:
  on_wake_word_detected:
    - voice_assistant.start:
        wake_word: !lambda return wake_word;
  model: okay_nabu

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in esphome-docs.

[probot-esphome]

Hey there @OttoWinter, mind taking a look at this pull request as it has been labeled with an integration (api) you are listed as a code owner for? Thanks!
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[probot-esphome]

Hey there @kahrendt, mind taking a look at this pull request as it has been labeled with an integration (micro_wake_word) you are listed as a code owner for? Thanks!
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