Fix admin payment form not being displayed on payment method change

When there are multiple payment methods, clicking the radio button for a payment method other than the first causes the payment forms to not be displayed.

How to replicate in sandbox:
1) Create an order through the admin until the payment state is reached
2) Create a new payment for the order (at this point the credit card form should be visible)
3) Click the Check radio button
4) Click the Credit Card radio button
5) The credit card form is no longer visible
exchange expires_at to starts_at to fix test
Restore "Add pry and pry debuggers to common spree dependencies"

This reverts commit 7006953963f65e69c14c6f88f2a2e87e83d8b20d.

Was breaking CI but that should be fixable by updating bundler on the CI.
Move set_shipments_cost call to Order#update_from_params

This stops the method from being called whenever Order#checkout_steps is called and thereby reduces some queries

This needs to be called in the checkout_specs to ensure that the state isn't jumped as long as this method is called.

Fixes #4898
Fixes #4979
Shipment cost is now included in spec totals.
Merge pull request #4977 from alexandremcosta/fix_promotion_spec

exchange expires_at to starts_at to fix test
Merge pull request #4974 from bonobos/fix/admin-payment-method-switch

Fix admin payment form not being displayed on payment method change
typo fix

Closes #4980
Remove js api key that was missed during 2469735fba9720d4cb0895576a197a375d569071
Order#finalize should use save!

save will silently ignore any errors. It is much better to raise an
error than to silently fail.
Merge pull request #4986 from athal7/remove-api-token

Remove js api key that was missed during 2469735fba9720d4cb0895576a197a3...
Order#merge! should use save!
Merge pull request #4989 from jhawthorn/save_bang

Use save! when modifying the order
Add blank to ShippingMethod's TaxCategory select

Addresses https://github.com/spree/spree/issues/4914

Now ShippingMethods whose `tax_category` is `nil` will display a blank selector rather than falsely displaying the first TaxCategory in the system.

Note that due to the UI implementation it appears to be impossible to return to selecting `nil` after a TaxCategory has been selected.
Include Store in ControllerHelpers.
Set missing credit card attributes when possible. Fixes #4972
API Orders#show should only return the order json. Fixes #4979
Use prepend_before_filter to try calling before apply_coupon_code. refs #4926
Switch to cancancan to fix issues with custom abilities being unable to properly initialize sprees namespaced models.
Merge pull request #4978 from jordan-brough/restore-pry-debuggers

Restore "Add pry and pry debuggers to common spree dependencies"