[Tooling] Remove leftover references to Cocoapods

[iangmaia]

Related: AINFRA-479: Update scenarios and Fastfile after removing Cocoapods

Description

Removing final references to Cocoapods, following-up to WordPress-iOS#24156, WordPress-iOS#23958.

My main goal was to remove the Buildkite annotation pods mention, but when I searched for references in the project folder I found a few in the WordPress/WordPress.xcodeproj/project.pbxproj file, so I also removed them.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[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	27609
	Version	PR #24526
	Bundle ID	com.jetpack.alpha
	Commit	eccf0f5
	Installation URL	4lo1tgvmsqt8g

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 WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Configuration	Release-Alpha
	Build Number	27609
	Version	PR #24526
	Bundle ID	org.wordpress.alpha
	Commit	eccf0f5
	Installation URL	4dgb0d7tunao0

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

[mokagio]

Thanks @iangmaia !