Restore Old Package & Offering Initializer APIs

[fire-at-will]

Context

In release 5.23.0, we unintentionally broke the public API for the Offering and Package initializers by adding a non-optional webCheckoutUrl: URL? parameter.

The breaking changes were introduced in the these PRs/commits:

• https://github.com/RevenueCat/purchases-ios/pull/5049
• https://github.com/RevenueCat/purchases-ios/pull/5062/commits/5ff1c6fbf48b71c480ce18717750b780a1e30729

Description

This PR restores the previous API by re-introducing new public initializers for these structs that omit the webCheckoutUrl parameter, matching the API contracts prior to 5.23.0. It also adds these re-introduced constructors to the API testers.

This PR introduces entirely new convenience initializers rather than adding a default value of nil to the existing ones, because initializers with default parameter values aren’t exposed to Objective-C. Simply adding a default would not restore the original Objective-C API.

[emerge-tools[bot]]

📸 Snapshot Test

1 modified, 704 unchanged

Name	Added	Removed	Modified	Renamed	Unchanged	Errored	Approval
RevenueCat com.revenuecat.PaywallsTester.mac-catalyst-optimized-for-mac	0	0	0	0	235	0	N/A
RevenueCat com.revenuecat.PaywallsTester.mac-catalyst-scaled-to-match-ipad	0	0	1	0	234	0	✅ Approved
RevenueCat com.revenuecat.PaywallsTester	0	0	0	0	235	0	N/A

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[fire-at-will]

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