fix(types): add missing file fields to ThreadBroadcastMessageEvent

[srtaalej]

Summary

Fixes #2762.

ThreadBroadcastMessageEvent was missing fields that Slack sends when a thread reply with an attached file is also sent to the channel. This adds them as optional fields, matching FileShareMessageEvent:

• files?: File[]
• upload?: boolean
• display_as_bot?: boolean
• parent_user_id?: string

I reproduced this with a Bolt app subscribed to message.channels:

• Broadcast with a file: all four fields are present in the payload.
• Text-only broadcast: none of the four fields are present, including parent_user_id. That's why every field is optional.

x_files (present on FileShareMessageEvent) was not sent in either case, so it isn't added here.

This also adds a tsd test in packages/types/test/events/message.test-d.ts and a patch changeset for @slack/types.

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[changeset-bot]

🦋 Changeset detected

Latest commit: d9642d5

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@slack/types	Patch

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.44%. Comparing base (b3190fd) to head (d9642d5).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2763      +/-   ##
==========================================
- Coverage   89.45%   89.44%   -0.01%     
==========================================
  Files          65       65              
  Lines       10525    10525              
  Branches      478      478              
==========================================
- Hits         9415     9414       -1     
- Misses       1079     1080       +1     
  Partials       31       31              

Flag	Coverage Δ
cli-hooks	89.32% <ø> (ø)
cli-test	89.32% <ø> (ø)
logger	89.32% <ø> (ø)
oauth	89.32% <ø> (ø)
socket-mode	89.32% <ø> (ø)
web-api	89.32% <ø> (ø)
webhook	89.32% <ø> (ø)

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[srtaalej]

codecov failing by .01% 😬 can we increase the threshold for cases like this? cc. @zimeg @WilliamBergamin

[zimeg]

@srtaalej LGTM! Thanks for keeping this most current and including a test 🧪

[zimeg]

can we increase the threshold for cases like this?

These tests use the typescript typechecker to confirm correctness instead of unit tests with particular coverage. I fear this @slack/types package might not have actual coverage but I'm now curious if we can omit it from the @codecov checks too...