[RN][CI]: add safety net to prevent accidental LOCAL podspec versions

[kieran-osgood-shopify]

What changes are you making?

Adds a new blocking CI step to ensure that the pod file doesn't point to local references
This would cause a podfile lock mismatch later in the flow, this is a fast fail with a clearer error message to avoid confusion and wasted time debugging

---

Before you merge

Important

• I've added tests to support my implementation
• I have read and agree with the Contribution Guidelines
• I have read and agree with the Code of Conduct
• I've updated the relevant platform README (platforms/swift/README.md and/or platforms/android/README.md)

---

Releasing a new Swift version?

• I have bumped the version in ShopifyCheckoutKit.podspec
• I have bumped the version in platforms/swift/Sources/ShopifyCheckoutKit/ShopifyCheckoutKit.swift
• I have updated platforms/swift/CHANGELOG.md
• I have updated the SwiftPM/CocoaPods version snippets in platforms/swift/README.md (major version only)

Releasing a new Android version?

• I have bumped the versionName in platforms/android/lib/build.gradle
• I have updated platforms/android/CHANGELOG.md
• I have updated the Gradle/Maven version snippets in platforms/android/README.md

Tip

See the Contributing documentation for the full release process per platform.

[kieran-osgood-shopify]

• [RN][CI] Validation CLI for releases #192
• [RN][CI]: add safety net to prevent accidental LOCAL podspec versions #229 👈 (View in Graphite)
• [RN]: use published artifacts for RN native builds/tests #227 : 1 other dependent PR (#228 )
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

React Native — Coverage Report

Lines	Statements	Branches	Functions
	91.59% (316/345)	87.25% (178/204)	100% (82/82)

[kieran-osgood-shopify]

Merge activity

• May 29, 10:31 AM UTC: A user started a stack merge that includes this pull request via Graphite.
• May 29, 10:33 AM UTC: Graphite rebased this pull request as part of a merge.
• May 29, 10:49 AM UTC: @kieran-osgood-shopify merged this pull request with Graphite.