Handle new error codes from the media upload endpoint

[maxme]

Expected behavior

In case of an error during media upload, we should show the exact error to help the user take a decision.

The list of errors are defined here in Calypso. Most interesting are:

• rest_upload_limited_space
• rest_upload_file_too_big
• rest_upload_user_quota_exceeded

Note that these error codes are actually stored in the message field. Here is an sample response we get from the https://public-api.wordpress.com/rest/v1.1/sites/{SITE_ID}/media/new/ API endpoint in case of an upload on a quota limited site:

{
    "error": "upload_error",
    "message": "rest_upload_user_quota_exceeded|You have used your space quota. Please delete files before uploading. Back"
}

• On the network side (FluxC): It would be a good idea to split the error message (something linke .split("|")), store the error code in the FluxC event that is sent back to the app.
• On the UI, we should handle that error and display the message correctly instead of showing a generic message. This must be done:
  • In the media library.
  • In the editor.

Actual behavior

We show a generic error in the editor and in the media library:

Media Library	Editor

More details on paaHJt-17e-p2

WPiOS related ticket: https://github.com/wordpress-mobile/WordPress-iOS/issues/14401

[designsimply]

When an image upload fails for an image larger than 2650 x 2650 pixels on a Bluehost Jetpack site, there is a very generic error message both in the Media and the Editor—would it be possible to improve this error message in the app?

Media upload failed. CURL error 28: Operation timed out after 30001 mil…

^{Tested with WPAndroid 17.1-rc-1 on Pixel 3 Android 11.}

The following error is shown on the Bluehost WP Admin Media screen if I try uploading the same image there, and it's a much better error message:

Post-processing of the image failed likely because the server is busy or does not have enough resources. Uploading a smaller image may help. Suggested maximum size is 2500 pixels.

^{Image upload error for an 5.1 MB, 4032 x 3024 image seen at testingallthetime.com/wp-admin/upload.php — Bluehost site running Jetpack 9.5.}

In the WordPress app, I think we could improve this error even further if we ask users to try adjusting their image optimization settings in App Settings.

^{My Site > Account > App Setings > Maximum Image Size settings seen in WPAndroid 17.1-rc-1 on Pixel 3 Android 11.}

^{(internal reference: 6510-gh-Automattic/jpop-issues#issuecomment-815361481)}

[mchowning]

There have been some improvements in this area, which are discussed in https://github.com/wordpress-mobile/gutenberg-mobile/issues/2448