Support for Multiple Package handling in fulfillment app

[AjinkyaM1]

What is the motivation for adding/enhancing this feature?

We need to add support for multiple package handling. Currently, when adding multiple boxes for a single order, each box creates a separate shipment. We want to update the system so that:

1. Multiple boxes can be added under a single shipment.

Additional information

Adding the MR link for the backend development: https://git.hotwax.co/commerce/oms/-/merge_requests/5227/diffs#313dea4a953f64e8aa92afefe2e67a105a253298

[Adameddy26]

Completed testing the feature over v2.13.0 and have found below mentioned issues.

Issues found during testing -

1. If auto shipping label generation is enabled for a facility and the label is auto-generated (when any change in the shipment package is made), a new label is generated but does not get displayed on the UI. The user needs to refresh the URL to see it.
   https://jam.dev/c/d9e4809d-fedf-4f09-af4d-185e55c24bec

2. If the above case is tested using a carrier that does not support multi-package shipments, a new label is generated, but the shipment method card appears disabled even after refreshing the URL.
   https://jam.dev/c/462d0e70-4a0c-4ee2-b91a-a9cb23eadccf

3. The Update Order API is not working when the user tries to generate a shipping label using a carrier for which the shipping label is not generating (for any reason) and then clicks the Save button. Here, clicking the Save button attempts to void the existing label, and if no label was pre-generated, the Update Order API throws an error.
   https://jam.dev/c/edebf89c-2ddd-4820-8e46-bc699936bd83

4. If user create multi package using a carrier(who doesn't supports multi package shipment) and then switch to different carrier(who supports multi package shipment) then the empty boxes remains there in the order and are not getting removed.If packages are added using carrier who does not support multi package functionality -> label generated and moved to completed- > void label and regenerate using carrier who supports multi package functionality -> unpack the order -> extra/empty packages are visible.
   https://jam.dev/c/c798d9c5-9676-4c56-9efc-83c3f72e8842
   Extra packages are not getting removed from DB and UI if there are multiple line items and one or more items are reported with issues.

5. Package type is incorrectly set to false value when user change in shipment package type of the selected shipment package, adds one more package and the save the changes.
   https://jam.dev/c/f34d4b86-5376-4cc8-a883-3f5454dd4ded

6. If two items are in different packages then two labels are generated separately but on UI only one is visible.

7. Shipment method not updating in modal when user fastly changes the carrier from the detail page and open the pack order modal

8. Generate label using Drivin(automated) - void - regenerate label using C807(manual) - shipment method field is blank.

9. In progress - Refresh the URL - Again pack - Return to main tab - Blank screen with loader.

10. Unpack - Boxes/packages are not visible - Refresh the URL - Packages now become visible.

11. If multi line items are present in a single order and order is moved to In progress from open the order details are not completely loaded.

[amansinghbais]

1 - Adding a new box and saving an order voids the old label and regenerates a new one asynchronously. This causes the label to be missing when refetching the order shipping labels. Need to either make it sync or look for other solution.

2 - [Here in the new flow we are adding the label to only those packages which have items on auto generation, resulting in some packages (created with old flow, means shipments created) without tracking code. Making inconsistent label generation.

Seems like we should clear empty shipments too while adding boxes, since now we are not adding label to the boxes.

3 - Investigate the backend implementation of the UpdateOrder API to identify and resolve this error.

4 - For carriers with multi-package support, packages are automatically removed when they contain no items. However, for carriers without multi-package support, a new shipment is created when adding a box, and there is no mechanism to remove packages without items.
Backend support should be added to handle the removal of empty packages (shipments) for carriers without multi-package support.

5 - When we change the boxType and save it, and then when we are refetching the packages the old boxType is coming it's due to the boxType of the boxes only gets saved if it's in use. If we are updating the box type of the package which is not in use then it will not get updated. It's expected behaviour.

6 - Based on current implementation in case of multiple label, we show only one on the UI but print all on view label. If we want to show all the labels on the UI can think of possible UI.

7, 8 - Addressed these issue in the following PR - #900

9, 10, 11 - Following issues are occuring due to slow data updation in Solr while fetching order detail. So when we pack/ unpack/pick order the updated data is refetched from solr but it will not get updated.