[CSE-10][external] Fixes for LocalDataset object instantiation

[JBWilkie]

Problem

• 1: When dataset items in folders are pulled in a flat structure, LocalDataset instantiation and the get_annotations() function doesn't work because we are constructing & checking image paths on the assumption they were pulled with folders
• 2: Changes introduced in IO-1445 broke Darwin JSON 1.0 compatibility with LocalDataset objects & get_annotations() in some scenarios

Much more problem detail is available in a comment in CSE-10

Solution

• 1: When instantiating a LocalDataset object or using get_annotations(), check if the release was pulled with folders and pass this down to the image path construction
• 2: When instantiating a LocalDataset object or using get_annotations(), check if the release is Darwin JSON 1.0 or 2.0, then pass this down to the relevant function(s)

Much more solution detail is available in a comment in CSE-10

Changelog

• Fixed false assumption that dataset releases with folders are always pulled with folders. This assumption led to issues creating LocalDataset objects and with the use of the get_annotations() function
• Fixed issue where Darwin JSON 1.0 was not compatible with LocalDataset objects of the get_annotations() function

[linear]

CSE-10 Multiple stems error when using get_annotations()

Client has a workaround so this is low priority, but needs investigation and PR if necessary

Originally reported in this Intercom conversation

[JBWilkie]

Note: This has failing tests at the moment, I need to:

• 1: Resolve them - There appears to be an issue where one test is loading a V2 dataset of 20 items, but one of the items is actually a V1 item
• 2: Resolve an issue with json_stream for video files with large frame_url fields. There appears to be an issue where if frame_url exceeds a certain size, then the stream breaks

I will raise this with someone soon to unblock the work

[JBWilkie]

Unrelated to the original ticket, but stage_id is str