Voice assist improvement - configurable conversation_id timeout

[jeffc]

What does this implement/fix?

Makes the timeout for the voice assist conversation_id configurable instead of a hard-coded 5 minutes. Partly addresses esphome/feature-requests#2812

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• [x ] 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): partly fixes esphome/feature-requests#2812

Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#4213

Test Environment

• [x ] ESP32
• ESP32 IDF
• ESP8266
• RP2040
• BK72xx
• RTL87xx

Example entry for config.yaml:

# Example config.yaml
voice_assistant:
  microphone: mic_i2s
  id: va
  noise_suppression_level: 2
  auto_gain: 31dBFS
  volume_multiplier: 8.0
  use_wake_word: false
  conversation_timeout: 60s
  media_player: media_out

Checklist:

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

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

• [ x] Documentation added/updated in esphome-docs.

[probot-esphome]

Hey there @jesserockz, mind taking a look at this pull request as it has been labeled with an integration (voice_assistant) you are listed as a code owner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 53.94%. Comparing base (4d8b5ed) to head (6294b87).
Report is 1265 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #7385      +/-   ##
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+ Coverage   53.70%   53.94%   +0.23%     
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  Files          50       50              
  Lines        9408     9676     +268     
  Branches     1654     1708      +54     
==========================================
+ Hits         5053     5220     +167     
- Misses       4056     4132      +76     
- Partials      299      324      +25     

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[jesserockz]

Looks good to me. Please fix the CI failures.

[esphome]

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks 👍

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