Add missing style attribute to RichTextElementParts.Date & friends

[Lexicality]

Summary

I noticed that the style attribute was missing when I tried to make a date bold.

Testing

Category

• slack_sdk.web.WebClient (sync/async) (Web API client)
• slack_sdk.webhook.WebhookClient (sync/async) (Incoming Webhook, response_url sender)
• slack_sdk.socket_mode (Socket Mode client)
• slack_sdk.signature (Request Signature Verifier)
• slack_sdk.oauth (OAuth Flow Utilities)
• slack_sdk.models (UI component builders)
• slack_sdk.scim (SCIM API client)
• slack_sdk.audit_logs (Audit Logs API client)
• slack_sdk.rtm_v2 (RTM client)
• /docs (Documents)
• /tutorial (PythOnBoardingBot tutorial)
• tests/integration_tests (Automated tests for this library)

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.
• I've run python3 -m venv .venv && source .venv/bin/activate && ./scripts/run_validation.sh after making the changes.

[codecov]

Codecov Report

❌ Patch coverage is 33.33333% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.12%. Comparing base (078ba76) to head (9a1f5d4).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
slack_sdk/models/blocks/block_elements.py	33.33%	4 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## main #1882 +/- ##
==========================================
- Coverage 84.13% 84.12% -0.02% 
==========================================
Files 117 117 Lines 13337 13340 +3 ==========================================
+ Hits 11221 11222 +1 - Misses 2116 2118 +2 

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[vegeris]

Thanks for making this update!