[deliver] Update upload_price_tier

[lukethoene]

Updates Pricing tier selection to correctly handle nil value

Motivation and Context

• Bug in upload_price_tier.rb resulting in neither pricing nor availability being selected

Resolves #21236

Description

This change adds safe nav operator to prevent NoMethodErrors when checking first app price, preventing failure to set pricing tier for new app listings.

Tested via creation of several new dummy apps to verify the pricing is set as expected.

Testing Steps

• Create a New App
• Verify pricing is set as expected

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[bartpowers]

👍 Works for me with this change

[anh1979]

Please, could anyone let this proceed, then?

[joshdholtz]

Looks good to me! I'll get a new version out tonight

Thanks for the fix! ❤️

[vincentisambart]

I'm sorry, but as I wrote (#21213 (comment)) in the very similar #21213, I don't think this fix is correct. This will probably end up making any app available in all territories.

[pedro380085]

Thank you for releasing this as part of 2.214.0!

[wesselj2]

I can confirm what @vincentisambart is saying. This is setting our apps to be available in all territories every time we submit and we have to manually change it.