build(deps): bump @slack/web-api from 7.14.1 to 7.15.0

Bumps [@slack/web-api](https://github.com/slackapi/node-slack-sdk) from 7.14.1 to 7.15.0.
- [Release notes](https://github.com/slackapi/node-slack-sdk/releases)
- [Commits](https://github.com/slackapi/node-slack-sdk/compare/@slack/web-api@7.14.1...@slack/web-api@7.15.0)

---
updated-dependencies:
- dependency-name: "@slack/web-api"
  dependency-version: 7.15.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package-lock.json

@@ -37,7 +37,7 @@
     "@actions/core": "^3.0.0",
     "@actions/github": "^9.0.0",
     "@slack/logger": "^4.0.0",
-    "@slack/web-api": "^7.14.1",
+    "@slack/web-api": "^7.15.0",
     "axios": "^1.13.6",
     "axios-retry": "^4.5.0",
     "flat": "^6.0.1",