[Tooling] Remove duplicate logging on CI

[AliSoftware]

Why?

Now that we've migrated to release-toolkit version 13.1, which includes wordpress-mobile/release-toolkit#638 that already handles inserting Buildkite-aware collapsible groups in CI logs for all repos, the custom logic that was added specifically in WPiOS Fastfile is no longer needed now that it's handled by the release-toolkit itself, and in fact keeping the existing logic in WPiOS' Fastfile duplicated the logs in CI

Testing

Look at the CI logs for this PR and confirm that the collapsible groups inserted in CI logs are no longer duplicated.

This is what it looked before, right after the project updated to release-toolkit version 13.1:

This is what it looks like now, without any duplication anymore:

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Configuration	Release-Alpha
	Build Number	27121
	Version	PR #24412
	Bundle ID	org.wordpress.alpha
	Commit	43eb3f4
	Installation URL	7icvu2hsflum8

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Configuration	Release-Alpha
	Build Number	27121
	Version	PR #24412
	Bundle ID	com.jetpack.alpha
	Commit	43eb3f4
	Installation URL	0872d17asdfvg

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.